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• tracing a linux kernel, function-by function (biggest only) with us timer

  - by osgx

  Hello I want to know, how does the linux kernel do some stuff (receiving a tcp packet). In what order main tcp functions are called. I want to see both interrupt handler (top half), bottom half and even work done by kernel after user calls "read()". How can I get a function trace from kernel with some linear time scale? I want to get a trace from single packet, not the profile of kernel when receiving 1000th of packets. Kernel is 2.6.18 or 2.6.23 (supported in my debian). I can add some patches to it.

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• make error in re-building ns2

  - by user3702405

  I have implemented a new routing protocol named AODV2 in ns-2.35. I am using ns-2.35 in fedora 13. All .cc files have a .o file with them that means recompilation is done. But I am getting an error in response to the 'make' command. Error is shown below: trace/cmu-trace.o: In function hdr_aodv2::access(Packet const*)': cmu-trace.cc:(.text._ZN9hdr_aodv26accessEPK6Packet[hdr_aodv2::access(Packet const*)]+0x7): undefined reference tohdr_aodv2::offset_2' collect2: ld returned 1 exit status make: * [ns] Error 1 I don't know how to remove this error, Can anyone help me please? Thanks, Naeem

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• GKSession sendDataToAllPeers including sendee?

  - by Typeoneerror

  I've got a number of devices connected over wifi using GameKit. I have a simple UIAlertView popping up when peers receive data. All but the sendee show this alert view when data is sent, so I'm wondering if that's a bug in my app or if that's expected behavior. Should call a method manually at the same on the sendee device? For example, if I wanted to send a "GameStart" packet to the 4 phones, the peers would call startGame: in the receiveData:fromPeer:inSession:context: method when it receives that packet and the sendee would just sendData and call startGame: on itself. Does that sound right or is there a way to include the sendee in the sendData list so that it responds exactly the same as all connected peers?

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• Reading PGP key information

  - by calccrypto

  can someone show a description of the information of what a pgp looks like if only the descriptions were there but not the actual information? something like (i dont remember if the values are correct): packet-type[4 bits], total length in bytes[16 bits], packet version type [4 bits], creation-time[32 bits], encryption-algorithm[8 bits], ...,etc,etc ive tried to understand rfc4880, but its tedious and confusing. so far, i am think i have extracted the 4 i wrote above, but i cant seem to get the rest of the information out. can anyone help? i know i can just find some pgp program, but the whole point of this is to allow me to learn how those programs work in the first place

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• Object to Network serialization - with an existing protocol

  - by cpf

  I'm writing a client for a server program written in C++. As is not unusual, all the networking protocol is in a format where packets can be easily memcopied into/out of a C++ structure (1 byte packet code, then different arrangements per packet type). I could do the same thing in C#, but is there an easier way, especially considering lots of the data is fixed-length char arrays that I want to play with as strings? Or should I just suck it up and convert types as needed? I've looked at using the ISerializable interface, but it doesnt look as low level as is required.

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• How can I get Syslogging to work on the JVM?

  - by Synesso

  I want to do syslogging from Java. There is a log4j appender, but it doesn't seem to work (for me anyway ... though Google results show many others with this issue still unresolved). I'm trying to debug the appender, so I've written the following script based upon RFC3164 It runs, but no logging appears in the syslog. // scala import java.io._ import java.net._ val ds = new DatagramSocket() val fullMsg = "<11>May 26 14:47:22 Hello World" val packet = new DatagramPacket(fullMsg.getBytes("UTF-8"), fullMsg.length, InetAddress.getLocalHost, 514) ds send packet ds.close I also tried using /bin/nc, but it doesn't work either. echo "<14>May 26 15:23:83 Hello world" > nc -u localhost 514 The Ubuntu command /usr/bin/logger does work, however. logger -p user.info hello world # logs: May 26 15:25:10 dsupport2 jem: hello world What could I be doing wrong?

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• how to reverse fill each entity of byte array?

  - by moon

  i want to prepare a byte buffer as a upd packet i want to fill each value in reverse order how can i do so in ansi c

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• Weird Datagrid / paint behaviour

  - by Shane.C

  The scenario: A method sends out a broadcast packet, and returned packets that are validated are deemed okay to be added as a row in my datagrid (The returned packets are from devices i want to add into my program). So for each packet returned, containing information about a device, i create a new row. This is done by first sending packets out, creating rows and adding them to a list of rows that are to be added, and then after 5 seconds (In which case all packets would have returned by then) i add the rows. Here's a few snippets of code. Here for each returned packet, i create a row and add it to a list; DataRow row = DGSource.NewRow(); row["Name"] = deviceName; row["Model"] = deviceModel; row["Location"] = deviceLocation; row["IP"] = finishedIP; row["MAC"] = finishedMac; row["Subnet"] = finishedSubnet; row["Gateway"] = finishedGateway; rowsToAdd.Add(row); Then when the timer elapses; void timerToAddRows_Elapsed(object sender, System.Timers.ElapsedEventArgs e) { timerToAddRows.Enabled = false; try { int count = 0; foreach (DataRow rowToAdd in rowsToAdd) { DGSource.Rows.Add(rowToAdd); count++; } rowsToAdd.Clear(); DGAutoDevices.InvokeEx(f => DGAutoDevices.Refresh()); lblNumberFound.InvokeEx(f => lblNumberFound.Text = count + " new devices found."); } catch { } } So at this point, each row has been added, and i call the re paint, by doing refresh. (Note: i've also tried refreshing the form itself, no avail). However, when the datagrid shows the rows, the scroll bar / datagrid seems to have weird behavour..for example i can't highlight anything with clicks (It's set to full row selection), and the scroll bar looks like so; Calling refresh doesn't work, although if i resize the window even 1 pixel, or minimize and maximise, the problem is solved. Other things to note : The method that get's the packets and adds the rows to the list, and then from the list to the datagrid runs in it's own thread. Any ideas as to something i might be missing here?

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• Raw socket implementation in windows?

  - by krishnakumar

  I need to create TCP/IP headers manually for my application. For that i used Raw socket. My system os is win xp (SP3). My code compiles fine :) but it throws a run time error: Initialising Winsock...Initialised successfully. Creating Raw TCP Socket...Raw TCP Socket Created successfully. Setting the socket in RAW mode...Successful. Enter hostname : 192.168.1.152 Resolving Hostname...Resolved. Enter Source IP : 192.168.1.151 Sending packet... Error sending Packet : 10022 I have set IP_HDRINCL to 1. What am i doing wrong? I switched off the firewall too but still get the same result.

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• What's causing "Unable to retrieve native address from ByteBuffer object"?

  - by r0u1i

  As a very novice Java programmer, I probably should not mess with that kind of things. Unfortunately, I'm using a library which have a method that accepts a ByteBuffer object and throws when I try to use it: Exception in thread "main" java.lang.NullPointerException: Unable to retrieve native address from ByteBuffer object Is it because I'm not using a non-direct buffer? edit: There's not a lot of my code there. The library I'm using is jNetPcap, and I'm trying to dump a packet to file. My code takes an existing packet, and extract a ByteBuffer out of it: byte[] bytes = m_packet.getByteArray(0, m_packet.size()); ByteBuffer buffer = ByteBuffer.wrap(bytes); Then it calls on of the dump methods of jNetPcap that takes a ByteBuffer.

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• Bit/Byte adressing - Little/Big-endnian

  - by code8230

  Consider the 16-Bit data packet below, which is sent through the network in network byte order ie Big Endian: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 (Byte num) 34 67 89 45 90 AB FF 23 65 37 56 C6 56 B7 00 00 (Value) Lets say 8945 is a 16 bit value. All others are 8 bit data bytes. On my system, which is little endian, how would the data be received and stored? Lets say, we are configured to receive 8 bytes at a time. RxBuff is the Rx buffer where data will be received. Buff is the storage buffer where data would be stored. Please point out which case is correct for data storage after reading 8 bytes at a time: 1) Buff[] = {0x34, 0x67, 0x45, 0x89, 0x90, 0xAB....... 0x00}; 2) Buff[] = {0x00, 0x00, .......0x67, 0x89, 0x45, 0x34}; Would the whole 16 bytes data be reversed or only the 2 bytes value contained in this packet?

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• iOS Development: How can I encapsulate a string in an NSData object?

  - by BeachRunnerJoe

  Hello. I'm building a multiplayer game on the iPhone and I need to send string data to the other players in the game. To do that, I need to encapsulate my NSString* string data in an NSData object somehow. Here's an example of how my code is structured... typedef struct { PACKETTYPE packetType; ??? stringToSend; //<---not sure how to store this } StringPacket; StringPacket msg; msg.packetType = STRING_PACKET; msg.stringToSend = ... // <---not sure what to do here NSData *packet = [NSData dataWithBytes:&msg length:sizeof(StringPacket)]; So my question is, if StringPacket is a struct defined in my header, what type should the stringToSend property be so that I can easily call the dataWithBytes method of NSData to encapsulate the packet data in an NSData object? Thanks for your wisdom!

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• how do i detect \r\n in a u_char type of buffer?

  - by aDi Adam

  i am trying to construct http content from packet sniffing in C. right now i am able to save all the packets in a file but i want to get rid of the headers in the first packet. they are also being saved as per they are a part of tcp payload. the actual body after the header starts after double "crlf" or \r\n\r\n in http response. how do i detect \r\n so that i can only save the following part of the buffer in the file. the buffer is u_char type. i cant figure out the command or the part i looked on google and other places but i mostly find c# commands, nothing in C.

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• OpenVPN: Connection established but can’t connect to server

  - by Maik

  I am trying to set up OpenVPN to allow me to connect a number of laptops to my network in a way that allows the laptops to connect to specific computers via HTTP (to e.g. a server management page) and windows shares (to access files) In the test environment my laptops live in a network with a 192.168.1.X address range. The host-network has a 10.66.77.X address range The server hosting the OpenVPN server has address 10.77.10.20. I need to access some application server web pages on this machine, accessible on various ports The server with the windows shares as well as some other web based pages I need to access is on address 10.66.77.20 The config files for server and laptop are attached below. The laptop establishes the VPN connection without problems, but I cannot access any of the machines, even a simple ping fails. Maybe a routing problem? The routing table for the laptop is shown below as well - every idea is appreciated! Thanks! Maik Server config file port 1194 dev tun tls-server ca /etc/openvpn/keys/ca.crt cert /etc/openvpn/keys/projects.crt key /etc/openvpn/keys/projects.key dh /etc/openvpn/keys/dh1024.pem server 10.8.0.0 255.255.255.0 ifconfig-pool-persist ipp.txt push "route 10.66.77.0 255.255.255.0" keepalive 10 60 inactive 600 route 10.8.0.1 255.255.255.0 user openvpn group openvpn persist-tun persist-key verb 4 client config file dev tun proto udp remote SERVERADDR 1194 resolv-retry infinite nobind persist-key persist-tun ca ca.crt cert accountingLaptop.crt key accountingLaptop.key ns-cert-type server comp-lzo verb 3 Resulting routing table on client laptop C:\Documents and Settings\User>route print =========================================================================== Interface List 0x1 ........................... MS TCP Loopback interface 0x2 ...00 23 5a 9b 64 9b ...... Atheros AR8132 PCI-E Fast Ethernet Controller - Packet Scheduler Miniport 0x3 ...00 24 2c 35 c9 6b ...... Dell Wireless 1395 WLAN Mini-Card - Packet Sched uler Miniport 0x4 ...00 ff 5e 03 43 9b ...... TAP-Win32 Adapter V9 - Packet Scheduler Miniport =========================================================================== =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 192.168.1.1 192.168.1.129 25 10.8.0.1 255.255.255.255 10.8.0.5 10.8.0.6 1 10.8.0.4 255.255.255.252 10.8.0.6 10.8.0.6 30 10.8.0.6 255.255.255.255 127.0.0.1 127.0.0.1 30 10.66.77.0 255.255.255.0 10.8.0.5 10.8.0.6 1 10.255.255.255 255.255.255.255 10.8.0.6 10.8.0.6 30 127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1 192.168.1.0 255.255.255.0 192.168.1.129 192.168.1.129 25 192.168.1.129 255.255.255.255 127.0.0.1 127.0.0.1 25 192.168.1.255 255.255.255.255 192.168.1.129 192.168.1.129 25 224.0.0.0 240.0.0.0 10.8.0.6 10.8.0.6 30 224.0.0.0 240.0.0.0 192.168.1.129 192.168.1.129 25 255.255.255.255 255.255.255.255 10.8.0.6 2 1 255.255.255.255 255.255.255.255 10.8.0.6 10.8.0.6 1 255.255.255.255 255.255.255.255 192.168.1.129 192.168.1.129 1 Default Gateway: 192.168.1.1 =========================================================================== Persistent Routes: None

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• Cisco VPN Client dropping connection

  - by IT Team

  Using Windows XP and Cisco VPN client version 5.0.4.xxx to connect to a remote customer site. We are able to establish the connection and start an RDP session, but within 1-2 minutes the connection drops and the VPN connection disconnects. The PC making the connection is on a DMZ which is NATed to a public IP address. If we move the PC directly onto the internet without being on the DMZ the connection works and we don't encounter any disconnects. We use a PIX 515E running 7.2.4 and don't have any problems with similar setups connecting to other customer sites from the DMZ. The VPN setup on the client side is pretty basic, using IPSec over TCP port 10000. Not sure what device they are using on the peer, but my guess would be an ASA. Any idea as to what the problem would be? Below is the logs from the VPN client when the problem occurs. The real IP address has been changed to: RemotePeerIP. 4 14:39:30.593 09/23/09 Sev=Info/4 CM/0x63100024 Attempt connection with server "RemotePeerIP" 5 14:39:30.593 09/23/09 Sev=Info/6 CM/0x6310002F Allocated local TCP port 1942 for TCP connection. 6 14:39:30.796 09/23/09 Sev=Info/4 IPSEC/0x63700008 IPSec driver successfully started 7 14:39:30.796 09/23/09 Sev=Info/4 IPSEC/0x63700014 Deleted all keys 8 14:39:30.796 09/23/09 Sev=Info/6 IPSEC/0x6370002C Sent 256 packets, 0 were fragmented. 9 14:39:30.796 09/23/09 Sev=Info/6 IPSEC/0x63700020 TCP SYN sent to RemotePeerIP, src port 1942, dst port 10000 10 14:39:30.796 09/23/09 Sev=Info/6 IPSEC/0x6370001C TCP SYN-ACK received from RemotePeerIP, src port 10000, dst port 1942 11 14:39:30.796 09/23/09 Sev=Info/6 IPSEC/0x63700021 TCP ACK sent to RemotePeerIP, src port 1942, dst port 10000 12 14:39:30.796 09/23/09 Sev=Warning/3 IPSEC/0xA370001C Bad cTCP trailer, Rsvd 26984, Magic# 63697672h, trailer len 101, MajorVer 13, MinorVer 10 13 14:39:30.796 09/23/09 Sev=Info/4 CM/0x63100029 TCP connection established on port 10000 with server "RemotePeerIP" 14 14:39:31.296 09/23/09 Sev=Info/4 CM/0x63100024 Attempt connection with server "RemotePeerIP" 15 14:39:31.296 09/23/09 Sev=Info/6 IKE/0x6300003B Attempting to establish a connection with RemotePeerIP. 16 14:39:31.296 09/23/09 Sev=Info/4 IKE/0x63000013 SENDING ISAKMP OAK AG (SA, KE, NON, ID, VID(Xauth), VID(dpd), VID(Frag), VID(Unity)) to RemotePeerIP 17 14:39:36.296 09/23/09 Sev=Info/4 IKE/0x63000021 Retransmitting last packet! 18 14:39:36.296 09/23/09 Sev=Info/4 IKE/0x63000013 SENDING ISAKMP OAK AG (Retransmission) to RemotePeerIP 19 14:39:41.296 09/23/09 Sev=Info/4 IKE/0x63000021 Retransmitting last packet! 20 14:39:41.296 09/23/09 Sev=Info/4 IKE/0x63000013 SENDING ISAKMP OAK AG (Retransmission) to RemotePeerIP 21 14:39:46.296 09/23/09 Sev=Info/4 IKE/0x63000021 Retransmitting last packet! 22 14:39:46.296 09/23/09 Sev=Info/4 IKE/0x63000013 SENDING ISAKMP OAK AG (Retransmission) to RemotePeerIP 23 14:39:51.328 09/23/09 Sev=Info/4 IKE/0x63000017 Marking IKE SA for deletion (I_Cookie=AEFC3FFF0405BBD6 R_Cookie=0000000000000000) reason = DEL_REASON_PEER_NOT_RESPONDING 24 14:39:51.828 09/23/09 Sev=Info/4 IKE/0x6300004B Discarding IKE SA negotiation (I_Cookie=AEFC3FFF0405BBD6 R_Cookie=0000000000000000) reason = DEL_REASON_PEER_NOT_RESPONDING 25 14:39:51.828 09/23/09 Sev=Info/4 CM/0x63100014 Unable to establish Phase 1 SA with server "RemotePeerIP" because of "DEL_REASON_PEER_NOT_RESPONDING" 26 14:39:51.828 09/23/09 Sev=Info/5 CM/0x63100025 Initializing CVPNDrv 27 14:39:51.828 09/23/09 Sev=Info/4 CM/0x6310002D Resetting TCP connection on port 10000 28 14:39:51.828 09/23/09 Sev=Info/6 CM/0x63100030 Removed local TCP port 1942 for TCP connection. 29 14:39:51.828 09/23/09 Sev=Info/6 CM/0x63100046 Set tunnel established flag in registry to 0. 30 14:39:51.828 09/23/09 Sev=Info/4 IKE/0x63000001 IKE received signal to terminate VPN connection 31 14:39:52.328 09/23/09 Sev=Info/6 IPSEC/0x63700023 TCP RST sent to RemotePeerIP, src port 1942, dst port 10000 32 14:39:52.328 09/23/09 Sev=Info/4 IPSEC/0x63700014 Deleted all keys 33 14:39:52.328 09/23/09 Sev=Info/4 IPSEC/0x63700014 Deleted all keys 34 14:39:52.328 09/23/09 Sev=Info/4 IPSEC/0x63700014 Deleted all keys 35 14:39:52.328 09/23/09 Sev=Info/4 IPSEC/0x6370000A IPSec driver successfully stopped Thank you for any help you can provide.

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• Linux pptp client stops working after several hours

  - by Aron Rotteveel

  Here's the situation: Setup: 1 Windows Server 2008 machine acting as a Domain Controller and RRAS server 1 CentOS machine in a datacentre located elsewhere PPTP client running on CentOS machine, connected to the DC via When I connect to the DC, everything is working fine. I have set up a static IP for the dialup connection in my RRAS server so that the CentOS machine is automatically assigned the IP 192.168.1.240. Inside the VPN, it is not possible to access this machine on the local IP-address. Perfect. However, after several hours, it simply seems to stop working (IE: I cannot ping to or from this machine on the local network). The strange thing is, however: The DC shows the VPN client as still being connected The CentOS machine shows the network interface as being up There are no entries in my /var/log/messages that indicate a problem Output from ifconfig: ppp0 Link encap:Point-to-Point Protocol inet addr:192.168.1.240 P-t-P:192.168.1.160 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1396 Metric:1 RX packets:43 errors:0 dropped:0 overruns:0 frame:0 TX packets:58 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:3 RX bytes:4511 (4.4 KiB) TX bytes:15071 (14.7 KiB) Output from route -n: 192.168.1.160 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0 192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 ppp0 I have the following in my ip-up.local: route add -net 192.168.1.0 netmask 255.255.255.0 dev ppp0 The situation can be easily fixed by issueing a killall pppd and re-connecting. However, I obviously do not want to do this every X-hours or so. I have tried running pppd with both the debug as the kdebug flag but cannot find the cause of this problem. Currently, my ppp0 network interface seems to be running and the last log lines mentioning it are: Feb 19 14:10:40 graviton pppd[10934]: local IP address 192.168.1.240 Feb 19 14:10:40 graviton pppd[10934]: remote IP address 192.168.1.160 Feb 19 14:10:40 graviton pppd[10934]: Script /etc/ppp/ip-up started (pid 10952) Feb 19 14:10:40 graviton pppd[10934]: Script /etc/ppp/ip-up finished (pid 10952), status = 0x0 Feb 19 14:11:27 graviton pptp[10935]: anon log[decaps_gre:pptp_gre.c:414]: buffering packet 190 (expecting 189, lost or reordered) Feb 19 14:11:37 graviton pptp[10942]: anon log[logecho:pptp_ctrl.c:677]: Echo Request received. Feb 19 14:11:37 graviton pptp[10942]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 6 'Echo-Reply' Feb 19 14:12:37 graviton pptp[10942]: anon log[logecho:pptp_ctrl.c:677]: Echo Request received. Feb 19 14:12:37 graviton pptp[10942]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 6 'Echo-Reply' Feb 19 14:12:37 graviton pptp[10942]: anon log[logecho:pptp_ctrl.c:677]: Echo Reply received. Feb 19 14:13:37 graviton pptp[10942]: anon log[logecho:pptp_ctrl.c:677]: Echo Reply received. Feb 19 14:14:37 graviton pptp[10942]: anon log[logecho:pptp_ctrl.c:677]: Echo Reply received. Feb 19 14:15:37 graviton pptp[10942]: anon log[logecho:pptp_ctrl.c:677]: Echo Reply received. Feb 19 14:16:37 graviton pptp[10942]: anon log[logecho:pptp_ctrl.c:677]: Echo Reply received. Feb 19 14:19:37 graviton pptp[10942]: anon log[logecho:pptp_ctrl.c:677]: Echo Reply received. Feb 19 14:19:37 graviton pptp[10942]: anon log[logecho:pptp_ctrl.c:679]: no more Echo Reply/Request packets will be reported. I have enabled the persist option. The network interface is still running, but it is still impossible to send data through the VPN. Any help is appreciated.

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• VPN in Ubuntu fails every time

  - by fazpas

  I am trying to setup a vpn connection in Ubuntu 10.04 to use the service from relakks.com I used the network manager to add the vpn connection and the settings are: Gateway: pptp.relakks.com Username: user Password: pwd IPv4 Settings: Automatic (VPN) Advanced: MSCHAP & MSCHAPv2 checked Use point-to-point encryption (security:default) Allow BSD data compression checked Allow deflate data compression checked Use TCP header compression checked The connection always fail, here is the syslog: Jun 27 20:11:56 desktop NetworkManager: <info> Starting VPN service 'org.freedesktop.NetworkManager.pptp'... Jun 27 20:11:56 desktop NetworkManager: <info> VPN service 'org.freedesktop.NetworkManager.pptp' started (org.freedesktop.NetworkManager.pptp), PID 2064 Jun 27 20:11:56 desktop NetworkManager: <info> VPN service 'org.freedesktop.NetworkManager.pptp' just appeared, activating connections Jun 27 20:11:56 desktop NetworkManager: <info> VPN plugin state changed: 3 Jun 27 20:11:56 desktop NetworkManager: <info> VPN connection 'Relakks' (Connect) reply received. Jun 27 20:11:56 desktop pppd[2067]: Plugin /usr/lib/pppd/2.4.5//nm-pptp-pppd-plugin.so loaded. Jun 27 20:11:56 desktop pppd[2067]: pppd 2.4.5 started by root, uid 0 Jun 27 20:11:56 desktop NetworkManager: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/ppp1, iface: ppp1) Jun 27 20:11:56 desktop NetworkManager: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/ppp1, iface: ppp1): no ifupdown configuration found. Jun 27 20:11:56 desktop pppd[2067]: Using interface ppp1 Jun 27 20:11:56 desktop pppd[2067]: Connect: ppp1 <--> /dev/pts/0 Jun 27 20:11:56 desktop pptp[2071]: nm-pptp-service-2064 log[main:pptp.c:314]: The synchronous pptp option is NOT activated Jun 27 20:11:57 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 1 'Start-Control-Connection-Request' Jun 27 20:11:58 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_disp:pptp_ctrl.c:739]: Received Start Control Connection Reply Jun 27 20:11:58 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_disp:pptp_ctrl.c:773]: Client connection established. Jun 27 20:11:58 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 7 'Outgoing-Call-Request' Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_disp:pptp_ctrl.c:858]: Received Outgoing Call Reply. Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_disp:pptp_ctrl.c:897]: Outgoing call established (call ID 0, peer's call ID 1024). Jun 27 20:11:59 desktop kernel: [ 56.564074] Inbound IN=ppp0 OUT= MAC= SRC=93.182.139.2 DST=186.110.76.26 LEN=61 TOS=0x00 PREC=0x00 TTL=52 ID=40460 DF PROTO=47 Jun 27 20:11:59 desktop kernel: [ 56.944054] Inbound IN=ppp0 OUT= MAC= SRC=93.182.139.2 DST=186.110.76.26 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=40461 DF PROTO=47 Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[pptp_read_some:pptp_ctrl.c:544]: read returned zero, peer has closed Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[callmgr_main:pptp_callmgr.c:258]: Closing connection (shutdown) Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 12 'Call-Clear-Request' Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[pptp_read_some:pptp_ctrl.c:544]: read returned zero, peer has closed Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[call_callback:pptp_callmgr.c:79]: Closing connection (call state) Jun 27 20:11:59 desktop pppd[2067]: Modem hangup Jun 27 20:11:59 desktop pppd[2067]: Connection terminated. Jun 27 20:11:59 desktop NetworkManager: <info> VPN plugin failed: 1 Jun 27 20:11:59 desktop NetworkManager: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp1, iface: ppp1) Jun 27 20:11:59 desktop pppd[2067]: Exit. Does someone can identify something in the syslog? I've been googling and reading about pptp but couldn't find anything about the error "read returned zero, peer has closed"

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• Users loggin to 3Com switches authenticated by radius not getting admin priv and no access available

  - by 3D1L

  Hi, Following the setup that I have for my Cisco devices, I got some basic level of functionality authenticating users that loggin to 3Com switches authenticated against a RADIUS server. Problem is that I can not get the user to obtain admin privileges. I'm using Microsoft's IAS service. According to 3Com documentation when configuring the access policy on IAS the value of 010600000003 have to be used to specify admin access level. That value have to be input in the Dial-in profile section: 010600000003 - indicates admin privileges 010600000002 - manager 010600000001 - monitor 010600000000 - visitor Here is the configuration on the switch: radius scheme system server-type standard primary authentication XXX.XXX.XXX.XXX accounting optional key authentication XXXXXX key accounting XXXXXX domain system scheme radius-scheme system local-user admin service-type ssh telnet terminal level 3 local-user manager service-type ssh telnet terminal level 2 local-user monitor service-type ssh telnet terminal level 1 The configuration is working with the IAS server because I can check user login events with the Eventviewer tool. Here is the output of the DISPLAY RADIUS command at the switch: [4500]disp radius SchemeName =system Index=0 Type=standard Primary Auth IP =XXX.XXX.XXX.XXX Port=1645 State=active Primary Acct IP =127.0.0.1 Port=1646 State=active Second Auth IP =0.0.0.0 Port=1812 State=block Second Acct IP =0.0.0.0 Port=1813 State=block Auth Server Encryption Key= XXXXXX Acct Server Encryption Key= XXXXXX Accounting method = optional TimeOutValue(in second)=3 RetryTimes=3 RealtimeACCT(in minute)=12 Permitted send realtime PKT failed counts =5 Retry sending times of noresponse acct-stop-PKT =500 Quiet-interval(min) =5 Username format =without-domain Data flow unit =Byte Packet unit =1 Total 1 RADIUS scheme(s). 1 listed Here is the output of the DISPLAY DOMAIN and DISPLAY CONNECTION commands after users log into the switch: [4500]display domain 0 Domain = system State = Active RADIUS Scheme = system Access-limit = Disable Domain User Template: Idle-cut = Disable Self-service = Disable Messenger Time = Disable Default Domain Name: system Total 1 domain(s).1 listed. [4500]display connection Index=0 ,Username=admin@system IP=0.0.0.0 Index=2 ,Username=user@system IP=xxx.xxx.xxx.xxx On Unit 1:Total 2 connections matched, 2 listed. Total 2 connections matched, 2 listed. [4500] Here is the DISP RADIUS STATISTICS: [4500] %Apr 2 00:23:39:957 2000 4500 SHELL/5/LOGIN:- 1 - ecajigas(xxx.xxx.xxx.xxx) in un it1 logindisp radius stat state statistic(total=1048): DEAD=1046 AuthProc=0 AuthSucc=0 AcctStart=0 RLTSend=0 RLTWait=2 AcctStop=0 OnLine=2 Stop=0 StateErr=0 Received and Sent packets statistic: Unit 1........................................ Sent PKT total :4 Received PKT total:1 Resend Times Resend total 1 1 2 1 Total 2 RADIUS received packets statistic: Code= 2,Num=1 ,Err=0 Code= 3,Num=0 ,Err=0 Code= 5,Num=0 ,Err=0 Code=11,Num=0 ,Err=0 Running statistic: RADIUS received messages statistic: Normal auth request , Num=1 , Err=0 , Succ=1 EAP auth request , Num=0 , Err=0 , Succ=0 Account request , Num=1 , Err=0 , Succ=1 Account off request , Num=0 , Err=0 , Succ=0 PKT auth timeout , Num=0 , Err=0 , Succ=0 PKT acct_timeout , Num=3 , Err=1 , Succ=2 Realtime Account timer , Num=0 , Err=0 , Succ=0 PKT response , Num=1 , Err=0 , Succ=1 EAP reauth_request , Num=0 , Err=0 , Succ=0 PORTAL access , Num=0 , Err=0 , Succ=0 Update ack , Num=0 , Err=0 , Succ=0 PORTAL access ack , Num=0 , Err=0 , Succ=0 Session ctrl pkt , Num=0 , Err=0 , Succ=0 RADIUS sent messages statistic: Auth accept , Num=0 Auth reject , Num=0 EAP auth replying , Num=0 Account success , Num=0 Account failure , Num=0 Cut req , Num=0 RecError_MSG_sum:0 SndMSG_Fail_sum :0 Timer_Err :0 Alloc_Mem_Err :0 State Mismatch :0 Other_Error :0 No-response-acct-stop packet =0 Discarded No-response-acct-stop packet for buffer overflow =0 The other problem is that when the RADIUS server is not available I can not log in to the switch. The switch have 3 local accounts but none of them works. How can I specify the switch to use the local accounts in case that the RADIUS service is not available?

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• How to transfer data between two networks efficiently

  - by Tono Nam

  I would like to transfer files between two places over the internet. Right now I have a VPN and I am able to browse, download and transfer files. So my question is not really how to transfer the files; Instead, I would like to use the most efficient approach because the two places constantly share a lot of data. The reason why I want to get rid of the VPN is because it is two slow. Having high upload speed is very expensive/impossible in residential places so I would like to use a different approach. I was thinking about using programs such as http://www.dropbox.com . The problem with Dropbox is that the free version comes with only 2 GB of storage. I think the deals they offer are OK and I might be willing to pay to get that increase in speed. But I am concerned with the speed of transferring data. Dropbox will upload the file to their server then send it from the server to the other location. I would like it to be even faster. Anyway I was thinking why not create a program myself. This is the algorithm that I was thinking of. Let me know if it sounds too crazy. (Remember my goal is to transfer files as fast as possible) Things that I will use in this algorithm: Server on the internet called S (Has fast download and upload speed. I pay to host a website and some services in there. I want to take advantage of it.) Client A at location 1 Client B at location 2 So lets say at location 1, 20 large files are created and need to be transferred to location 2. Client A compresses the files with the highest compression ratio possible. Client A starts sending data via UDP to client B. Because I am using UDP I will include the sequence number on each packet. Have server S help speed up things. For example every time a packet is lost we can use Server S to inform client A that it needs to resend a packet. Anyways I think this approach will increase the transfer rate. I do not know if it is possible to start sending data while it is being compressed. Or if it is possible to start decompressing data even if we are not done receiving the whole file. Maybe it will be faster to start sending the files right away without compressing. If I knew that I will always be sending large text files then I will obviously use the compression. I need this as a general algorithm. So I guess my question is could I increase performance by using UDP instead of TCP and by using an extra server to keep track of lost packets? And how should I compress files before sending? Compressing a 1 GB file with the highest compression ratio takes about 1 hour! I would like to take advantage of that time by sending it as it is being compressed.

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• VPN in Ubuntu fails every time

  - by fazpas

  I am trying to setup a vpn connection in Ubuntu 10.04 to use the service from relakks.com I used the network manager to add the vpn connection and the settings are: Gateway: pptp.relakks.com Username: user Password: pwd IPv4 Settings: Automatic (VPN) Advanced: MSCHAP & MSCHAPv2 checked Use point-to-point encryption (security:default) Allow BSD data compression checked Allow deflate data compression checked Use TCP header compression checked The connection always fail, here is the syslog: Jun 27 20:11:56 desktop NetworkManager: <info> Starting VPN service 'org.freedesktop.NetworkManager.pptp'... Jun 27 20:11:56 desktop NetworkManager: <info> VPN service 'org.freedesktop.NetworkManager.pptp' started (org.freedesktop.NetworkManager.pptp), PID 2064 Jun 27 20:11:56 desktop NetworkManager: <info> VPN service 'org.freedesktop.NetworkManager.pptp' just appeared, activating connections Jun 27 20:11:56 desktop NetworkManager: <info> VPN plugin state changed: 3 Jun 27 20:11:56 desktop NetworkManager: <info> VPN connection 'Relakks' (Connect) reply received. Jun 27 20:11:56 desktop pppd[2067]: Plugin /usr/lib/pppd/2.4.5//nm-pptp-pppd-plugin.so loaded. Jun 27 20:11:56 desktop pppd[2067]: pppd 2.4.5 started by root, uid 0 Jun 27 20:11:56 desktop NetworkManager: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/ppp1, iface: ppp1) Jun 27 20:11:56 desktop NetworkManager: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/ppp1, iface: ppp1): no ifupdown configuration found. Jun 27 20:11:56 desktop pppd[2067]: Using interface ppp1 Jun 27 20:11:56 desktop pppd[2067]: Connect: ppp1 <--> /dev/pts/0 Jun 27 20:11:56 desktop pptp[2071]: nm-pptp-service-2064 log[main:pptp.c:314]: The synchronous pptp option is NOT activated Jun 27 20:11:57 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 1 'Start-Control-Connection-Request' Jun 27 20:11:58 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_disp:pptp_ctrl.c:739]: Received Start Control Connection Reply Jun 27 20:11:58 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_disp:pptp_ctrl.c:773]: Client connection established. Jun 27 20:11:58 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 7 'Outgoing-Call-Request' Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_disp:pptp_ctrl.c:858]: Received Outgoing Call Reply. Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_disp:pptp_ctrl.c:897]: Outgoing call established (call ID 0, peer's call ID 1024). Jun 27 20:11:59 desktop kernel: [ 56.564074] Inbound IN=ppp0 OUT= MAC= SRC=93.182.139.2 DST=186.110.76.26 LEN=61 TOS=0x00 PREC=0x00 TTL=52 ID=40460 DF PROTO=47 Jun 27 20:11:59 desktop kernel: [ 56.944054] Inbound IN=ppp0 OUT= MAC= SRC=93.182.139.2 DST=186.110.76.26 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=40461 DF PROTO=47 Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[pptp_read_some:pptp_ctrl.c:544]: read returned zero, peer has closed Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[callmgr_main:pptp_callmgr.c:258]: Closing connection (shutdown) Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 12 'Call-Clear-Request' Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[pptp_read_some:pptp_ctrl.c:544]: read returned zero, peer has closed Jun 27 20:11:59 desktop pptp[2079]: nm-pptp-service-2064 log[call_callback:pptp_callmgr.c:79]: Closing connection (call state) Jun 27 20:11:59 desktop pppd[2067]: Modem hangup Jun 27 20:11:59 desktop pppd[2067]: Connection terminated. Jun 27 20:11:59 desktop NetworkManager: <info> VPN plugin failed: 1 Jun 27 20:11:59 desktop NetworkManager: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp1, iface: ppp1) Jun 27 20:11:59 desktop pppd[2067]: Exit. Does someone can identify something in the syslog? I've been googling and reading about pptp but couldn't find anything about the error "read returned zero, peer has closed"

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• Expert iptables help needed?

  - by Asad Moeen

  After a detailed analysis, I collected these details. I am under a UDP Flood which is more of application dependent. I run a Game-Server and an attacker is flooding me with "getstatus" query which makes the GameServer respond by making the replies to the query which cause output to the attacker's IP as high as 30mb/s and server lag. Here are the packet details, Packet starts with 4 bytes 0xff and then getstatus. Theoretically, the packet is like "\xff\xff\xff\xffgetstatus " Now that I've tried a lot of iptables variations like state and rate-limiting along side but those didn't work. Rate Limit works good but only when the Server is not started. As soon as the server starts, no iptables rule seems to block it. Anyone else got more solutions? someone asked me to contact the provider and get it done at the Network/Router but that looks very odd and I believe they might not do it since that would also affect other clients. Responding to all those answers, I'd say: Firstly, its a VPS so they can't do it for me. Secondly, I don't care if something is coming in but since its application generated so there has to be a OS level solution to block the outgoing packets. At least the outgoing ones must be stopped. Secondly, its not Ddos since just 400kb/s input generates 30mb/s output from my GameServer. That never happens in a D-dos. Asking the provider/hardware level solution should be used in that case but this one is different. And Yes, Banning his IP stops the flood of outgoing packets but he has many more IP-Addresses as he spoofs his original so I just need something to block him automatically. Even tried a lot of Firewalls but as you know they are just front-ends to iptables so if something doesn't work on iptables, what would the firewalls do? These were the rules I tried, iptables -A INPUT -p udp -m state --state NEW -m recent --set --name DDOS --rsource iptables -A INPUT -p udp -m state --state NEW -m recent --update --seconds 1 --hitcount 5 --name DDOS --rsource -j DROP It works for the attacks on un-used ports but when the server is listening and responding to the incoming queries by the attacker, it never works. Okay Tom.H, your rules were working when I modified them somehow like this: iptables -A INPUT -p udp -m length --length 1:1024 -m recent --set --name XXXX --rsource iptables -A INPUT -p udp -m string --string "xxxxxxxxxx" --algo bm --to 65535 -m recent --update --seconds 1 --hitcount 15 --name XXXX --rsource -j DROP They worked for about 3 days very good where the string "xxxxxxxxx" would be rate-limited, blocked if someone flooded and also didn't affect the clients. But just today, I tried updating the chain to try to remove a previously blocked IP so for that I had to flush the chain and restore this rule ( iptables -X and iptables -F ), some clients were already connected to servers including me. So restoring the rules now would also block some of the clients string completely while some are not affected. So does this mean I need to restart the server or why else would this happen because the last time the rules were working, there was no one connected?

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• Linux Kernel not passing through multicast UDP packets

  - by buecking

  Recently I've set up a new Ubuntu Server 10.04 and noticed my UDP server is no longer able to see any multicast data sent to the interface, even after joining the multicast group. I've got the exact same set up on two other Ubuntu 8.04.4 LTS machines and there is no problem receiving data after joining the same multicast group. The ethernet card is a Broadcom netXtreme II BCM5709 and the driver used is: b $ ethtool -i eth1 driver: bnx2 version: 2.0.2 firmware-version: 5.0.11 NCSI 2.0.5 bus-info: 0000:01:00.1 I'm using smcroute to manage my multicast registrations. b$ smcroute -d b$ smcroute -j eth1 233.37.54.71 After joining the group ip maddr shows the newly added registration. b$ ip maddr 1: lo inet 224.0.0.1 inet6 ff02::1 2: eth0 link 33:33:ff:40:c6:ad link 01:00:5e:00:00:01 link 33:33:00:00:00:01 inet 224.0.0.1 inet6 ff02::1:ff40:c6ad inet6 ff02::1 3: eth1 link 01:00:5e:25:36:47 link 01:00:5e:25:36:3e link 01:00:5e:25:36:3d link 33:33:ff:40:c6:af link 01:00:5e:00:00:01 link 33:33:00:00:00:01 inet 233.37.54.71 <------- McastGroup. inet 224.0.0.1 inet6 ff02::1:ff40:c6af inet6 ff02::1 So far so good, I can see that I'm receiving data for this multicast group. b$ sudo tcpdump -i eth1 -s 65534 host 233.37.54.71 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth1, link-type EN10MB (Ethernet), capture size 65534 bytes 09:30:09.924337 IP 192.164.1.120.58848 > 233.37.54.71.15572: UDP, length 212 09:30:09.947547 IP 192.164.1.120.58848 > 233.37.54.71.15572: UDP, length 212 09:30:10.108378 IP 192.164.1.120.58866 > 233.37.54.71.15574: UDP, length 268 09:30:10.196841 IP 192.164.1.120.58848 > 233.37.54.71.15572: UDP, length 212 ... I can also confirm that the interface is receiving mcast packets. b $ ethtool -S eth1 | grep mcast_pack rx_mcast_packets: 103998 tx_mcast_packets: 33 Now here's the problem. When I try to capture the traffic using a simple ruby UDP server I receive zero data! Here's a simple server that reads data send on port 15572 and prints the first two characters. This works on the two 8.04.4 Ubuntu Servers, but not the 10.04 server. require 'socket' s = UDPSocket.new s.bind("", 15572) 5.times do text, sender = s.recvfrom(2) puts text end If I send a UDP packet crafted in ruby to localhost, the server receives it and prints out the first two characters. So I know that the server above is working correctly. irb(main):001:0> require 'socket' => true irb(main):002:0> s = UDPSocket.new => #<UDPSocket:0x7f3ccd6615f0> irb(main):003:0> s.send("I2 XXX", 0, 'localhost', 15572) When I check the protocol statistics I see that InMcastPkts is not increasing. While on the other 8.04 servers, on the same network, received a few thousands packets in 10 seconds. b $ netstat -sgu ; sleep 10 ; netstat -sgu IcmpMsg: InType3: 11 OutType3: 11 Udp: 446 packets received 4 packets to unknown port received. 0 packet receive errors 461 packets sent UdpLite: IpExt: InMcastPkts: 4654 <--------- Same as below OutMcastPkts: 3426 InBcastPkts: 9854 InOctets: -1691733021 OutOctets: 51187936 InMcastOctets: 145207 OutMcastOctets: 109680 InBcastOctets: 1246341 IcmpMsg: InType3: 11 OutType3: 11 Udp: 446 packets received 4 packets to unknown port received. 0 packet receive errors 461 packets sent UdpLite: IpExt: InMcastPkts: 4656 <-------------- Same as above OutMcastPkts: 3427 InBcastPkts: 9854 InOctets: -1690886265 OutOctets: 51188788 InMcastOctets: 145267 OutMcastOctets: 109712 InBcastOctets: 1246341 If I try forcing the interface into promisc mode nothing changes. At this point I'm stuck. I've confirmed the kernel config has multicast enabled. Perhaps there are other config options I should be checking? b $ grep CONFIG_IP_MULTICAST /boot/config-2.6.32-23-server CONFIG_IP_MULTICAST=y Any thoughts on where to go from here?

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• From Binary to Data Structures

  - by Cédric Menzi

  Table of Contents Introduction PE file format and COFF header COFF file header BaseCoffReader Byte4ByteCoffReader UnsafeCoffReader ManagedCoffReader Conclusion History This article is also available on CodeProject Introduction Sometimes, you want to parse well-formed binary data and bring it into your objects to do some dirty stuff with it. In the Windows world most data structures are stored in special binary format. Either we call a WinApi function or we want to read from special files like images, spool files, executables or may be the previously announced Outlook Personal Folders File. Most specifications for these files can be found on the MSDN Libarary: Open Specification In my example, we are going to get the COFF (Common Object File Format) file header from a PE (Portable Executable). The exact specification can be found here: PECOFF PE file format and COFF header Before we start we need to know how this file is formatted. The following figure shows an overview of the Microsoft PE executable format. Source: Microsoft Our goal is to get the PE header. As we can see, the image starts with a MS-DOS 2.0 header with is not important for us. From the documentation we can read "...After the MS DOS stub, at the file offset specified at offset 0x3c, is a 4-byte...". With this information we know our reader has to jump to location 0x3c and read the offset to the signature. The signature is always 4 bytes that ensures that the image is a PE file. The signature is: PE\0\0. To prove this we first seek to the offset 0x3c, read if the file consist the signature. So we need to declare some constants, because we do not want magic numbers.   private const int PeSignatureOffsetLocation = 0x3c; private const int PeSignatureSize = 4; private const string PeSignatureContent = "PE";   Then a method for moving the reader to the correct location to read the offset of signature. With this method we always move the underlining Stream of the BinaryReader to the start location of the PE signature.   private void SeekToPeSignature(BinaryReader br) { // seek to the offset for the PE signagure br.BaseStream.Seek(PeSignatureOffsetLocation, SeekOrigin.Begin); // read the offset int offsetToPeSig = br.ReadInt32(); // seek to the start of the PE signature br.BaseStream.Seek(offsetToPeSig, SeekOrigin.Begin); }   Now, we can check if it is a valid PE image by reading of the next 4 byte contains the content PE.   private bool IsValidPeSignature(BinaryReader br) { // read 4 bytes to get the PE signature byte[] peSigBytes = br.ReadBytes(PeSignatureSize); // convert it to a string and trim \0 at the end of the content string peContent = Encoding.Default.GetString(peSigBytes).TrimEnd('\0'); // check if PE is in the content return peContent.Equals(PeSignatureContent); }   With this basic functionality we have a good base reader class to try the different methods of parsing the COFF file header. COFF file header The COFF header has the following structure: Offset Size Field 0 2 Machine 2 2 NumberOfSections 4 4 TimeDateStamp 8 4 PointerToSymbolTable 12 4 NumberOfSymbols 16 2 SizeOfOptionalHeader 18 2 Characteristics If we translate this table to code, we get something like this:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public MachineType Machine; public ushort NumberOfSections; public uint TimeDateStamp; public uint PointerToSymbolTable; public uint NumberOfSymbols; public ushort SizeOfOptionalHeader; public Characteristic Characteristics; } BaseCoffReader All readers do the same thing, so we go to the patterns library in our head and see that Strategy pattern or Template method pattern is sticked out in the bookshelf. I have decided to take the template method pattern in this case, because the Parse() should handle the IO for all implementations and the concrete parsing should done in its derived classes.   public CoffHeader Parse() { using (var br = new BinaryReader(File.Open(_fileName, FileMode.Open, FileAccess.Read, FileShare.Read))) { SeekToPeSignature(br); if (!IsValidPeSignature(br)) { throw new BadImageFormatException(); } return ParseInternal(br); } } protected abstract CoffHeader ParseInternal(BinaryReader br);   First we open the BinaryReader, seek to the PE signature then we check if it contains a valid PE signature and rest is done by the derived implementations. Byte4ByteCoffReader The first solution is using the BinaryReader. It is the general way to get the data. We only need to know which order, which data-type and its size. If we read byte for byte we could comment out the first line in the CoffHeader structure, because we have control about the order of the member assignment.   protected override CoffHeader ParseInternal(BinaryReader br) { CoffHeader coff = new CoffHeader(); coff.Machine = (MachineType)br.ReadInt16(); coff.NumberOfSections = (ushort)br.ReadInt16(); coff.TimeDateStamp = br.ReadUInt32(); coff.PointerToSymbolTable = br.ReadUInt32(); coff.NumberOfSymbols = br.ReadUInt32(); coff.SizeOfOptionalHeader = (ushort)br.ReadInt16(); coff.Characteristics = (Characteristic)br.ReadInt16(); return coff; }   If the structure is as short as the COFF header here and the specification will never changed, there is probably no reason to change the strategy. But if a data-type will be changed, a new member will be added or ordering of member will be changed the maintenance costs of this method are very high. UnsafeCoffReader Another way to bring the data into this structure is using a "magically" unsafe trick. As above, we know the layout and order of the data structure. Now, we need the StructLayout attribute, because we have to ensure that the .NET Runtime allocates the structure in the same order as it is specified in the source code. We also need to enable "Allow unsafe code (/unsafe)" in the project's build properties. Then we need to add the following constructor to the CoffHeader structure.   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { unsafe { fixed (byte* packet = &data[0]) { this = *(CoffHeader*)packet; } } } }   The "magic" trick is in the statement: this = *(CoffHeader*)packet;. What happens here? We have a fixed size of data somewhere in the memory and because a struct in C# is a value-type, the assignment operator = copies the whole data of the structure and not only the reference. To fill the structure with data, we need to pass the data as bytes into the CoffHeader structure. This can be achieved by reading the exact size of the structure from the PE file.   protected override CoffHeader ParseInternal(BinaryReader br) { return new CoffHeader(br.ReadBytes(Marshal.SizeOf(typeof(CoffHeader)))); }   This solution is the fastest way to parse the data and bring it into the structure, but it is unsafe and it could introduce some security and stability risks. ManagedCoffReader In this solution we are using the same approach of the structure assignment as above. But we need to replace the unsafe part in the constructor with the following managed part:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { IntPtr coffPtr = IntPtr.Zero; try { int size = Marshal.SizeOf(typeof(CoffHeader)); coffPtr = Marshal.AllocHGlobal(size); Marshal.Copy(data, 0, coffPtr, size); this = (CoffHeader)Marshal.PtrToStructure(coffPtr, typeof(CoffHeader)); } finally { Marshal.FreeHGlobal(coffPtr); } } }     Conclusion We saw that we can parse well-formed binary data to our data structures using different approaches. The first is probably the clearest way, because we know each member and its size and ordering and we have control about the reading the data for each member. But if add member or the structure is going change by some reason, we need to change the reader. The two other solutions use the approach of the structure assignment. In the unsafe implementation we need to compile the project with the /unsafe option. We increase the performance, but we get some security risks.

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• USB packets - receive wrong data

  - by regorianer

  i have a little python script which shows me the packets of an enocean device and does some events depending on the packet type. unfortunately it doesn't work because i'm getting wrong packets. Parts of the python script (used pySerial): Blockquote ser = serial.Serial('/dev/ttyUSB1',57600,bytesize = serial.EIGHTBITS,timeout = 1, parity = serial.PARITY_NONE , rtscts = 0) print 'clearing buffer' s = ser.read(10000) print 'start read' while 1: s = ser.read(1) for character in s: sys.stdout.write(" %s" % character.encode('hex')) print 'end' ser.close() output baudrate 57600: e0 e0 00 e0 00 e0 e0 e0 e0 e0 00 e0 e0 00 00 00 00 00 00 00 e0 e0 e0 00 00 00 00 e0 e0 e0 00 00 e0 e0 e0 e0 e0 00 e0 00 e0 e0 e0 e0 e0 00 e0 e0 00 00 00 00 00 00 e0 e0 e0 00 00 00 00 e0 e0 e0 00 00 e0 e0 e0 output baudrate 9600: a5 5a 0b 05 10 00 00 00 00 15 c4 56 20 6f a5 5a 0b 05 00 00 00 00 00 15 c4 56 20 5f linux terminal baudrate 57600: $stty -F /dev/ttyUSB1 57600 $stty < /dev/ttyUSB1 speed 57600 baud; line = 0; eof = ^A; min = 0; time = 0; -brkint -icrnl -imaxbel -opost -onlcr -isig -icanon -iexten -echo -echoe -echok -echoctl -echoke $while (true) do cat -A /dev/ttyUSB1 ; done myfile $hexdump -C myfile 00000000 4d 2d 60 4d 2d 60 5e 40 4d 2d 60 5e 40 4d 2d 60 |M-M-^@M-^@M-| 00000010 4d 2d 60 4d 2d 60 4d 2d 60 4d 2d 60 5e 40 4d 2d |M-M-M-M-^@M-| 00000020 60 4d 2d 60 5e 40 5e 40 5e 40 5e 40 5e 40 5e 40 |M-^@^@^@^@^@^@| 00000030 5e 40 4d 2d 60 4d 2d 60 4d 2d 60 5e 40 5e 40 5e |^@M-M-M-`^@^@^| 00000040 40 5e 40 4d 2d 60 4d 2d 60 4d 2d 60 |@^@M-M-M-`| 0000004c linux terminal baudrate 9600: $hexdump -C myfile2 00000000 5e 40 5e 55 4d 2d 44 56 30 4d 2d 3f 5e 40 5e 40 |^@^UM-DV0M-?^@^@| 00000010 5e 55 4d 2d 44 56 20 5f |^UM-DV _| 00000018 the specification says: 0x55 sync byte 1st 0xNNNN data length bytes (2 bytes) 0x07 opt length byte 0x01 type byte CRC, data, opt data und nochmal CRC but I'm not getting this packet structure. The output of the python script differs from the one I get via the terminal. I also wrote the python part with C, but the output is the same as with python As the USB receiver a BSC-BoR USB Receiver/Sender is used The EnOcean device is a simple button

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• Linux - Only first virtual interface can ping external gateway

  - by husvar

  I created 3 virtual interfaces with different mac addresses all linked to the same physical interface. I see that they successfully arp for the gw and they can ping (the request is coming in the packet capture in wireshark). However the ping utility does not count the responses. Does anyone knows the issue? I am running Ubuntu 14.04 in a VmWare. root@ubuntu:~# ip link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff inet6 fe80::20c:29ff:febc:fc8b/64 scope link valid_lft forever preferred_lft forever root@ubuntu:~# ip route sh root@ubuntu:~# ip link add link eth0 eth0.1 addr 00:00:00:00:00:11 type macvlan root@ubuntu:~# ip link add link eth0 eth0.2 addr 00:00:00:00:00:22 type macvlan root@ubuntu:~# ip link add link eth0 eth0.3 addr 00:00:00:00:00:33 type macvlan root@ubuntu:~# ip -4 link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff 18: eth0.1@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:11 brd ff:ff:ff:ff:ff:ff 19: eth0.2@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:22 brd ff:ff:ff:ff:ff:ff 20: eth0.3@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:33 brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip -4 addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever root@ubuntu:~# ip -4 route sh root@ubuntu:~# dhclient -v eth0.1 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.1/00:00:00:00:00:11 Sending on LPF/eth0.1/00:00:00:00:00:11 Sending on Socket/fallback DHCPDISCOVER on eth0.1 to 255.255.255.255 port 67 interval 3 (xid=0x568eac05) DHCPREQUEST of 192.168.1.145 on eth0.1 to 255.255.255.255 port 67 (xid=0x568eac05) DHCPOFFER of 192.168.1.145 from 192.168.1.254 DHCPACK of 192.168.1.145 from 192.168.1.254 bound to 192.168.1.145 -- renewal in 1473 seconds. root@ubuntu:~# dhclient -v eth0.2 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.2/00:00:00:00:00:22 Sending on LPF/eth0.2/00:00:00:00:00:22 Sending on Socket/fallback DHCPDISCOVER on eth0.2 to 255.255.255.255 port 67 interval 3 (xid=0x21e3114e) DHCPREQUEST of 192.168.1.146 on eth0.2 to 255.255.255.255 port 67 (xid=0x21e3114e) DHCPOFFER of 192.168.1.146 from 192.168.1.254 DHCPACK of 192.168.1.146 from 192.168.1.254 bound to 192.168.1.146 -- renewal in 1366 seconds. root@ubuntu:~# dhclient -v eth0.3 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.3/00:00:00:00:00:33 Sending on LPF/eth0.3/00:00:00:00:00:33 Sending on Socket/fallback DHCPDISCOVER on eth0.3 to 255.255.255.255 port 67 interval 3 (xid=0x11dc5f03) DHCPREQUEST of 192.168.1.147 on eth0.3 to 255.255.255.255 port 67 (xid=0x11dc5f03) DHCPOFFER of 192.168.1.147 from 192.168.1.254 DHCPACK of 192.168.1.147 from 192.168.1.254 bound to 192.168.1.147 -- renewal in 1657 seconds. root@ubuntu:~# ip -4 link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff 18: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:11 brd ff:ff:ff:ff:ff:ff 19: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:22 brd ff:ff:ff:ff:ff:ff 20: eth0.3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:33 brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip -4 addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 18: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.145/24 brd 192.168.1.255 scope global eth0.1 valid_lft forever preferred_lft forever 19: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.146/24 brd 192.168.1.255 scope global eth0.2 valid_lft forever preferred_lft forever 20: eth0.3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.147/24 brd 192.168.1.255 scope global eth0.3 valid_lft forever preferred_lft forever root@ubuntu:~# ip -4 route sh default via 192.168.1.254 dev eth0.1 192.168.1.0/24 dev eth0.1 proto kernel scope link src 192.168.1.145 192.168.1.0/24 dev eth0.2 proto kernel scope link src 192.168.1.146 192.168.1.0/24 dev eth0.3 proto kernel scope link src 192.168.1.147 root@ubuntu:~# arping -c 5 -I eth0.1 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.145 eth0.1 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 6.936ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.986ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 0.654ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 5.137ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.426ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# arping -c 5 -I eth0.2 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.146 eth0.2 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 5.665ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 3.753ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 16.500ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 3.287ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 32.438ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# arping -c 5 -I eth0.3 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.147 eth0.3 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 4.422ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.429ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.321ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 40.423ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.268ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# tcpdump -n -i eth0.1 -v & [1] 5317 root@ubuntu:~# ping -c5 -q -I eth0.1 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.145 eth0.1: 56(84) bytes of data. tcpdump: listening on eth0.1, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:37.612558 IP (tos 0x0, ttl 64, id 2595, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 2, length 64 13:18:37.618864 IP (tos 0x68, ttl 64, id 14493, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 2, length 64 13:18:37.743650 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:38.134997 IP (tos 0x0, ttl 128, id 23547, offset 0, flags [none], proto UDP (17), length 229) 192.168.1.86.138 > 192.168.1.255.138: NBT UDP PACKET(138) 13:18:38.614580 IP (tos 0x0, ttl 64, id 2596, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 3, length 64 13:18:38.793479 IP (tos 0x68, ttl 64, id 14495, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 3, length 64 13:18:39.151282 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:39.615612 IP (tos 0x0, ttl 64, id 2597, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 4, length 64 13:18:39.746981 IP (tos 0x68, ttl 64, id 14496, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 4, length 64 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4008ms rtt min/avg/max/mdev = 2.793/67.810/178.934/73.108 ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 9 packets captured 12 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.1 -v root@ubuntu:~# tcpdump -n -i eth0.2 -v & [1] 5320 root@ubuntu:~# ping -c5 -q -I eth0.2 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.146 eth0.2: 56(84) bytes of data. tcpdump: listening on eth0.2, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:41.536874 ARP, Ethernet (len 6), IPv4 (len 4), Reply 192.168.1.254 is-at 58:98:35:57:a0:70, length 46 13:18:41.536933 IP (tos 0x0, ttl 64, id 2599, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 1, length 64 13:18:41.539255 IP (tos 0x68, ttl 64, id 14507, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 1, length 64 13:18:42.127715 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:42.511725 IP (tos 0x0, ttl 64, id 2600, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 2, length 64 13:18:42.514385 IP (tos 0x68, ttl 64, id 14527, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 2, length 64 13:18:42.743856 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:43.511727 IP (tos 0x0, ttl 64, id 2601, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 3, length 64 13:18:43.513768 IP (tos 0x68, ttl 64, id 14528, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 3, length 64 13:18:43.637598 IP (tos 0x0, ttl 128, id 23551, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 255.255.255.255.17500: UDP, length 197 13:18:43.641185 IP (tos 0x0, ttl 128, id 23552, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 192.168.1.255.17500: UDP, length 197 13:18:43.641201 IP (tos 0x0, ttl 128, id 23553, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 255.255.255.255.17500: UDP, length 197 13:18:43.743890 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:44.510758 IP (tos 0x0, ttl 64, id 2602, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 4, length 64 13:18:44.512892 IP (tos 0x68, ttl 64, id 14538, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 4, length 64 13:18:45.510794 IP (tos 0x0, ttl 64, id 2603, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 5, length 64 13:18:45.519701 IP (tos 0x68, ttl 64, id 14539, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 5, length 64 13:18:49.287554 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:50.013463 IP (tos 0x0, ttl 255, id 50737, offset 0, flags [DF], proto UDP (17), length 73) 192.168.1.146.5353 > 224.0.0.251.5353: 0 [2q] PTR (QM)? _ipps._tcp.local. PTR (QM)? _ipp._tcp.local. (45) 13:18:50.218874 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:51.129961 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:52.197074 IP6 (hlim 255, next-header UDP (17) payload length: 53) 2001:818:d812:da00:200:ff:fe00:22.5353 > ff02::fb.5353: [udp sum ok] 0 [2q] PTR (QM)? _ipps._tcp.local. PTR (QM)? _ipp._tcp.local. (45) 13:18:54.128240 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 0 received, 100% packet loss, time 4000ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 13:18:54.657731 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:54.743174 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 25 packets captured 26 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.2 -v root@ubuntu:~# tcpdump -n -i eth0.3 icmp & [1] 5324 root@ubuntu:~# ping -c5 -q -I eth0.3 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.147 eth0.3: 56(84) bytes of data. tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0.3, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:56.373434 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 1, length 64 13:18:57.372116 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 2, length 64 13:18:57.381263 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 2, length 64 13:18:58.371141 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 3, length 64 13:18:58.373275 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 3, length 64 13:18:59.371165 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 4, length 64 13:18:59.373259 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 4, length 64 13:19:00.371211 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 5, length 64 13:19:00.373278 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 5, length 64 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 1 received, 80% packet loss, time 4001ms rtt min/avg/max/mdev = 13.666/13.666/13.666/0.000 ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 9 packets captured 10 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.3 icmp root@ubuntu:~# arp -n Address HWtype HWaddress Flags Mask Iface 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.1 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.2 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.3

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