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  • Any ideas why Ettercap filters aren't seeing packet data?

    - by Bryan
    I'm using an Ettercap filter to detect a query response coming back from a particular service on a remote machine. When I see a response from the service, I'm searching through the data in the packet to see if an offset is a specific value, and if so I'm changing the value at another offset. Trouble is, when I try this on a new virtual machine I built my Ettercap filter's no longer getting any data in the DATA.data variable available to it. if(ip.proto == TCP && tcp.src == 17867) { msg("Response seen!\n"); if(DATA.data + 2 == "\0x01") { msg("Flag detected!\n"); DATA.data + 5 = 0x09; } } The filter's getting applied to the traffic because "Response seen!" messages get printed out by Ettercap. However, "Flag detected!" messages do not. I think DATA.data is indeed empty because if I change my second "if" statement to check for DATA.data == "" then the "Flag detected!" message gets printed. Any ideas why this may be happening?! Also, if this is the wrong site to be asking questions like this, please let me know. I wasn't sure if it fit better here or somewhere like superuser or serverfault. By the way, this is a cross-post from StackOverflow... I should have posted on this forum instead I think. :)

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  • Can I make a "TCP packet modifier" using tun/tap and raw sockets?

    - by benhoyt
    I have a Linux application that talks TCP, and to help with analysis and statistics, I'd like to modify the data in some of the TCP packets that it sends out. I'd prefer to do this without hacking the Linux TCP stack. The idea I have so far is to make a bridge which acts as a "TCP packet modifier". My idea is to connect to the application via a tun/tap device on one side of the bridge, and to the network card via raw sockets on the other side of the bridge. My concern is that when you open a raw socket it still sends packets up to Linux's TCP stack, and so I couldn't modify them and send them on even if I wanted to. Is this correct? A pseudo-C-code sketch of the bridge looks like: tap_fd = open_tap_device("/dev/net/tun"); raw_fd = open_raw_socket(); for (;;) { select(fds = [tap_fd, raw_fd]); if (FD_ISSET(tap_fd, &fds)) { read_packet(tap_fd); modify_packet_if_needed(); write_packet(raw_fd); } if (FD_ISSET(raw_fd, &fds)) { read_packet(raw_fd); modify_packet_if_needed(); write_packet(tap_fd); } } Does this look possible, or are there other better ways of achieving the same thing? (TCP packet bridging and modification.)

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  • How do I get uri of HTTP packet with winpcap?

    - by Gtker
    Based on this article I can get all incoming packets. /* Callback function invoked by libpcap for every incoming packet */ void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data) { struct tm *ltime; char timestr[16]; ip_header *ih; udp_header *uh; u_int ip_len; u_short sport,dport; time_t local_tv_sec; /* convert the timestamp to readable format */ local_tv_sec = header->ts.tv_sec; ltime=localtime(&local_tv_sec); strftime( timestr, sizeof timestr, "%H:%M:%S", ltime); /* print timestamp and length of the packet */ printf("%s.%.6d len:%d ", timestr, header->ts.tv_usec, header->len); /* retireve the position of the ip header */ ih = (ip_header *) (pkt_data + 14); //length of ethernet header /* retireve the position of the udp header */ ip_len = (ih->ver_ihl & 0xf) * 4; uh = (udp_header *) ((u_char*)ih + ip_len); /* convert from network byte order to host byte order */ sport = ntohs( uh->sport ); dport = ntohs( uh->dport ); /* print ip addresses and udp ports */ printf("%d.%d.%d.%d.%d -> %d.%d.%d.%d.%d\n", ih->saddr.byte1, ih->saddr.byte2, ih->saddr.byte3, ih->saddr.byte4, sport, ih->daddr.byte1, ih->daddr.byte2, ih->daddr.byte3, ih->daddr.byte4, dport); } But how do I extract URI information in packet_handler?

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  • Bridging and iptables SNAT conflict

    - by sad_admin
    Hello I am working on a setup here and have it working with one minor exception. Devices on one side of my bridge aren't getting SNAT'd to the Internet. The Diagram / Overview: Primary_Network (Site_A) | | Internet ------- Linux_Bridge_GW (GW) | | Secondary/CoLo Site (Site_B) Here is the setup: 1.) Site_A has all the production servers and workstations. 2.) Site_B has a set of servers that we would like to fail-over to and also serve our internet facing services from. 3.) GW has two interfaces that are trunked and carrying the appropriate VLAN traffic (allow layer-2 propagation of traffic between sites) //this all works perfectly fine. 4.) The problem that is being encountered is, hosts from Site_B have their default GW at Site_A (same subnet) GW does not have IPs on the VLANs that are being passed. 5.) All hosts at Site_A can reach the Internet without problem. 6.) GW has an addresses on a subnet that is ONLY for Internet destined traffic. (This was done so that Websense would not have to parse unnecessary traffic. We use this VLAN as the monitor port's source on the switch where Websense is sitting). What I think is happening: 1.) Packet/Frame comes in on physdev at Site_B destined for Internet. 2.) Kernel sees packet, and forwards it out the other side of the bridge to that host's default GW. 3.) Site_A (containing core-network's Default-GW) sees that packet is destined for a host it doesn't know about, so it sends it to it's default GW (the linux bridge, since it's Internet bound). 4.) The kernel says "Hey, I've seen you before" and therefore doesn't do SNAT'ing on the packet and sends it out to the Internet where it's black-holed. Why I think it's happening: 1.) A tcpdump on the internet facing NIC shows the packet leaving the interface with the private address as it's source. What I would like: 1.) Have the packet SNAT'd. 2.) Something like the below would be awesome a.) packet comes in from Site_B b.) kernel sees that the packet is NOT destined for itself or any private address c.) kernel says "OK, well since you're destined for the Internet I'm going to send you out this interface rather than forward you to your normal default GW that's WAAAY over there." d.) packet comes in from internet and is sent out the appropriate bridge physdev depending on which site the host it's destined for is at. Thanks for any assistance or guidance that you are willing to offer. Best Regards, Sad Admin

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  • Unnecessary Java context switches

    - by Paul Morrison
    I have a network of Java Threads (Flow-Based Programming) communicating via fixed-capacity channels - running under WindowsXP. What we expected, based on our experience with "green" threads (non-preemptive), would be that threads would switch context less often (thus reducing CPU time) if the channels were made bigger. However, we found that increasing channel size does not make any difference to the run time. What seems to be happening is that Java decides to switch threads even though channels aren't full or empty (i.e. even though a thread doesn't have to suspend), which costs CPU time for no apparent advantage. Also changing Thread priorities doesn't make any observable difference. My question is whether there is some way of persuading Java not to make unnecessary context switches, but hold off switching until it is really necessary to switch threads - is there some way of changing Java's dispatching logic? Or is it reacting to something I didn't pay attention to?! Or are there other asynchronism mechanisms, e.g. Thread factories, Runnable(s), maybe even daemons (!). The answer appears to be non-obvious, as so far none of my correspondents has come up with an answer (including most recently two CS profs). Or maybe I'm missing something that's so obvious that people can't imagine my not knowing it... I've added the send and receive code here - not very elegant, but it seems to work...;-) In case you are wondering, I thought the goLock logic in 'send' might be causing the problem, but removing it temporarily didn't make any difference. I have added the code for send and receive... public synchronized Packet receive() { if (isDrained()) { return null; } while (isEmpty()) { try { wait(); } catch (InterruptedException e) { close(); return null; } if (isDrained()) { return null; } } if (isDrained()) { return null; } if (isFull()) { notifyAll(); // notify other components waiting to send } Packet packet = array[receivePtr]; array[receivePtr] = null; receivePtr = (receivePtr + 1) % array.length; //notifyAll(); // only needed if it was full usedSlots--; packet.setOwner(receiver); if (null == packet.getContent()) { traceFuncs("Received null packet"); } else { traceFuncs("Received: " + packet.toString()); } return packet; } synchronized boolean send(final Packet packet, final OutputPort op) { sender = op.sender; if (isClosed()) { return false; } while (isFull()) { try { wait(); } catch (InterruptedException e) { indicateOneSenderClosed(); return false; } sender = op.sender; } if (isClosed()) { return false; } try { receiver.goLock.lockInterruptibly(); } catch (InterruptedException ex) { return false; } try { packet.clearOwner(); array[sendPtr] = packet; sendPtr = (sendPtr + 1) % array.length; usedSlots++; // move this to here if (receiver.getStatus() == StatusValues.DORMANT || receiver.getStatus() == StatusValues.NOT_STARTED) { receiver.activate(); // start or wake up if necessary } else { notifyAll(); // notify receiver // other components waiting to send to this connection may also get // notified, // but this is handled by while statement } sender = null; Component.network.active = true; } finally { receiver.goLock.unlock(); } return true; }

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  • Python: Socket set source port number

    - by beratch
    Hi all, I'd like to send a specific UDP broadcast packet.. unfortunatly i need to send the udp packet from a very specific port for all packet I send. Let say I broadcast via UDP "BLABLAH", the server will only answer if my incoming packet source port was 1444, if not the packet is discarded. My broadcast socket setup look like this : s = socket(AF_INET,SOCK_DGRAM) s.setsockopt(SOL_SOCKET, SO_BROADCAST, 1) How can i do that (set the source port) in python ? Thanks!

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  • C# listview add items

    - by Eyla
    Greetings, I have a method to capture packets. after capturing I want to add each packet as a row in listview in runting time so as soon as I capture packet I want to add it to the list view. the problem that when I use items.Add() I will get overload argument error. please advice!! here is my code: private void packetCapturingThreadMethod() { Packet packet = null; int countOfPacketCaptures = 0; while ((packet = device.GetNextPacket()) != null) { packet = device.GetNextPacket(); if (packet is TCPPacket) { TCPPacket tcp = (TCPPacket)packet; myPacket tempPacket = new myPacket(); tempPacket.packetType = "TCP"; tempPacket.sourceAddress = Convert.ToString(tcp.SourceAddress); tempPacket.destinationAddress = Convert.ToString(tcp.DestinationAddress); tempPacket.sourcePort = Convert.ToString(tcp.SourcePort); tempPacket.destinationPort = Convert.ToString(tcp.DestinationPort); tempPacket.packetMessage = Convert.ToString(tcp.Data); packetsList.Add(tempPacket); string[] row = { packetsList[countOfPacketCaptures].packetType, packetsList[countOfPacketCaptures].sourceAddress, packetsList[countOfPacketCaptures].destinationAddress, packetsList[countOfPacketCaptures].sourcePort, packetsList[countOfPacketCaptures].destinationPort, packetsList[countOfPacketCaptures].packetMessage }; try { listView1.Items.Add(packetsList[countOfPacketCaptures].packetType, packetsList[countOfPacketCaptures].sourceAddress, packetsList[countOfPacketCaptures].destinationAddress, packetsList[countOfPacketCaptures].sourcePort, packetsList[countOfPacketCaptures].destinationPort, packetsList[countOfPacketCaptures].packetMessage) ; countOfPacketCaptures++; lblCapturesLabels.Text = Convert.ToString(countOfPacketCaptures);} catch (Exception e) { } } else if (packet is UDPPacket) { UDPPacket udp = (UDPPacket)packet; myPacket tempPacket = new myPacket(); tempPacket.packetType = "UDP"; tempPacket.sourceAddress = Convert.ToString(udp.SourceAddress); tempPacket.destinationAddress = Convert.ToString(udp.DestinationAddress); tempPacket.sourcePort = Convert.ToString(udp.SourcePort); tempPacket.destinationPort = Convert.ToString(udp.DestinationPort); tempPacket.packetMessage = Convert.ToString(udp.Data); packetsList.Add(tempPacket); string[] row = { packetsList[countOfPacketCaptures].packetType, packetsList[countOfPacketCaptures].sourceAddress, packetsList[countOfPacketCaptures].destinationAddress, packetsList[countOfPacketCaptures].sourcePort, packetsList[countOfPacketCaptures].destinationPort, packetsList[countOfPacketCaptures].packetMessage }; try { dgwPacketInfo.Rows.Add(row); countOfPacketCaptures++; lblCapturesLabels.Text = Convert.ToString(countOfPacketCaptures); } catch (Exception e) { } } } }

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  • Python and libpcap. find source mac address of packet.

    - by Shamanu4
    Hello! I'm writing python program to build mac-address cache using pcap. But pcap module for python has no good documentation. I have found this page http://pylibpcap.sourceforge.net/ with code example and it works fine. Can anybody modify this example to make it able to show the source mac-address for each packet? Or point me to the documentation where I can read about it ...

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  • How do I modify a HTTP response packet with winpcap?

    - by httpinterpret
    There are two problems here: What if content is encoded:gzip... Do I also need to change the header part to make the HTTP packet valid(checksums if any?) UPDATE Can someone with actual experience elaborate the steps involved? I'm using winpcap and bpf tcp and src port 80 to filter the traffic,so my job lies in this callback function: void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data)

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  • iphone problem receiving UDP packets

    - by SooDesuNe
    I'm using sendto() and recvfrom() to send some simple packets via UDP over WiFI. I've tried using two phones, and a simulator, the results I'm getting are: Packets sent from phones - recieved by simulator Packets sent from simulator - simulator recvfrom remains blocking. Packets sent from phones - other phone recvfrom remains blocking. I'm not sure how to start debugging this one, since the simulator/mac is able to receive the the packets, but the phones don't appear to be getting the message. A slight aside, do I need to keep my packets below the MTU for my network? Or is fragmentation handled by the OS or some other lower level software? UPDATE: I forgot to include the packet size and structure. I'm transmitting: typedef struct PacketForTransmission { int32_t packetTypeIdentifier; char data[64]; // size to fit my biggest struct } PacketForTransmission; of which the char data[64] is: typedef struct PacketHeader{ uint32_t identifier; uint32_t datatype; } PacketHeader; typedef struct BasePacket{ PacketHeader header; int32_t cardValue; char sendingDeviceID[41]; //dont forget to save room for the NULL terminator! } BasePacket; typedef struct PositionPacket{ BasePacket basePacket; int32_t x; int32_t y; } PositionPacket; sending packet is like: PositionPacket packet; bzero(&packet, sizeof(packet)); //fill packet with it's associated data PacketForTransmission transmissionPacket; transmissionPacket.packetTypeIdentifier = kPositionPacketType; memcpy(&transmissionPacket.data, (void*)&packet, sizeof(packet)); //put the PositionPacket into data[64] size_t sendResult = sendto(_socket, &transmissionPacket, sizeof(transmissionPacket), 0, [address bytes], [address length]); NSLog(@"packet sent of size: %i", sendResult); and recieving packets is like: while(1){ char dataBuffer[8192]; struct sockaddr addr; socklen_t socklen = sizeof(addr); ssize_t len = recvfrom(_socket, dataBuffer, sizeof(dataBuffer), 0, &addr, &socklen); //continues blocking here NSLog(@"packet recieved of length: %i", len); //do some more stuff }

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  • Is post-sudden-power-loss filesystem corruption on an SSD drive's ext3 partition "expected behavior"?

    - by Jeremy Friesner
    My company makes an embedded Debian Linux device that boots from an ext3 partition on an internal SSD drive. Because the device is an embedded "black box", it is usually shut down the rude way, by simply cutting power to the device via an external switch. This is normally okay, as ext3's journalling keeps things in order, so other than the occasional loss of part of a log file, things keep chugging along fine. However, we've recently seen a number of units where after a number of hard-power-cycles the ext3 partition starts to develop structural issues -- in particular, we run e2fsck on the ext3 partition and it finds a number of issues like those shown in the output listing at the bottom of this Question. Running e2fsck until it stops reporting errors (or reformatting the partition) clears the issues. My question is... what are the implications of seeing problems like this on an ext3/SSD system that has been subjected to lots of sudden/unexpected shutdowns? My feeling is that this might be a sign of a software or hardware problem in our system, since my understanding is that (barring a bug or hardware problem) ext3's journalling feature is supposed to prevent these sorts of filesystem-integrity errors. (Note: I understand that user-data is not journalled and so munged/missing/truncated user-files can happen; I'm specifically talking here about filesystem-metadata errors like those shown below) My co-worker, on the other hand, says that this is known/expected behavior because SSD controllers sometimes re-order write commands and that can cause the ext3 journal to get confused. In particular, he believes that even given normally functioning hardware and bug-free software, the ext3 journal only makes filesystem corruption less likely, not impossible, so we should not be surprised to see problems like this from time to time. Which of us is right? Embedded-PC-failsafe:~# ls Embedded-PC-failsafe:~# umount /mnt/unionfs Embedded-PC-failsafe:~# e2fsck /dev/sda3 e2fsck 1.41.3 (12-Oct-2008) embeddedrootwrite contains a file system with errors, check forced. Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Invalid inode number for '.' in directory inode 46948. Fix<y>? yes Directory inode 46948, block 0, offset 12: directory corrupted Salvage<y>? yes Entry 'status_2012-11-26_14h13m41.csv' in /var/log/status_logs (46956) has deleted/unused inode 47075. Clear<y>? yes Entry 'status_2012-11-26_10h42m58.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47076. Clear<y>? yes Entry 'status_2012-11-26_11h29m41.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47080. Clear<y>? yes Entry 'status_2012-11-26_11h42m13.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47081. Clear<y>? yes Entry 'status_2012-11-26_12h07m17.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47083. Clear<y>? yes Entry 'status_2012-11-26_12h14m53.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47085. Clear<y>? yes Entry 'status_2012-11-26_15h06m49.csv' in /var/log/status_logs (46956) has deleted/unused inode 47088. Clear<y>? yes Entry 'status_2012-11-20_14h50m09.csv' in /var/log/status_logs (46956) has deleted/unused inode 47073. Clear<y>? yes Entry 'status_2012-11-20_14h55m32.csv' in /var/log/status_logs (46956) has deleted/unused inode 47074. Clear<y>? yes Entry 'status_2012-11-26_11h04m36.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47078. Clear<y>? yes Entry 'status_2012-11-26_11h54m45.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47082. Clear<y>? yes Entry 'status_2012-11-26_12h12m20.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47084. Clear<y>? yes Entry 'status_2012-11-26_12h33m52.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47086. Clear<y>? yes Entry 'status_2012-11-26_10h51m59.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47077. Clear<y>? yes Entry 'status_2012-11-26_11h17m09.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47079. Clear<y>? yes Entry 'status_2012-11-26_12h54m11.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47087. Clear<y>? yes Pass 3: Checking directory connectivity '..' in /etc/network/run (46948) is <The NULL inode> (0), should be /etc/network (46953). Fix<y>? yes Couldn't fix parent of inode 46948: Couldn't find parent directory entry Pass 4: Checking reference counts Unattached inode 46945 Connect to /lost+found<y>? yes Inode 46945 ref count is 2, should be 1. Fix<y>? yes Inode 46953 ref count is 5, should be 4. Fix<y>? yes Pass 5: Checking group summary information Block bitmap differences: -(208264--208266) -(210062--210068) -(211343--211491) -(213241--213250) -(213344--213393) -213397 -(213457--213463) -(213516--213521) -(213628--213655) -(213683--213688) -(213709--213728) -(215265--215300) -(215346--215365) -(221541--221551) -(221696--221704) -227517 Fix<y>? yes Free blocks count wrong for group #6 (17247, counted=17611). Fix<y>? yes Free blocks count wrong (161691, counted=162055). Fix<y>? yes Inode bitmap differences: +(47089--47090) +47093 +47095 +(47097--47099) +(47101--47104) -(47219--47220) -47222 -47224 -47228 -47231 -(47347--47348) -47350 -47352 -47356 -47359 -(47457--47488) -47985 -47996 -(47999--48000) -48017 -(48027--48028) -(48030--48032) -48049 -(48059--48060) -(48062--48064) -48081 -(48091--48092) -(48094--48096) Fix<y>? yes Free inodes count wrong for group #6 (7608, counted=7624). Fix<y>? yes Free inodes count wrong (61919, counted=61935). Fix<y>? yes embeddedrootwrite: ***** FILE SYSTEM WAS MODIFIED ***** embeddedrootwrite: ********** WARNING: Filesystem still has errors ********** embeddedrootwrite: 657/62592 files (24.4% non-contiguous), 87882/249937 blocks Embedded-PC-failsafe:~# Embedded-PC-failsafe:~# e2fsck /dev/sda3 e2fsck 1.41.3 (12-Oct-2008) embeddedrootwrite contains a file system with errors, check forced. Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Directory entry for '.' in ... (46948) is big. Split<y>? yes Missing '..' in directory inode 46948. Fix<y>? yes Setting filetype for entry '..' in ... (46948) to 2. Pass 3: Checking directory connectivity '..' in /etc/network/run (46948) is <The NULL inode> (0), should be /etc/network (46953). Fix<y>? yes Pass 4: Checking reference counts Inode 2 ref count is 12, should be 13. Fix<y>? yes Pass 5: Checking group summary information embeddedrootwrite: ***** FILE SYSTEM WAS MODIFIED ***** embeddedrootwrite: 657/62592 files (24.4% non-contiguous), 87882/249937 blocks Embedded-PC-failsafe:~# Embedded-PC-failsafe:~# e2fsck /dev/sda3 e2fsck 1.41.3 (12-Oct-2008) embeddedrootwrite: clean, 657/62592 files, 87882/249937 blocks

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  • In terms of loss of volume or corruption, is failure probability of an Amazon EBS volume 'x', indepe

    - by Tony Morgan
    In terms of loss of volume or corruption, is failure probability of an Amazon EBS* volume 'x', independent of the failure of another volume 'y'. Amazon states[1] AFR** of between 0.1%-0.5%, lets say 0.5%, 0.005. To restate the question is the AFR composed of two EBSs mirrored actually 0.005*0.005 = 0.000025? To be clear I'm not interested in high availability here, just very high durability. *EBS = elastic block storage (amazons persistant disks) **AFR = annual failure rate. [1] http://aws.amazon.com/ebs/

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  • Upcasting without any added data fields.

    - by Benjamin Manns
    In my project I have a generic Packet class. I would like to be able to upcast to other classes (like LoginPacket or MovePacket). The base class contains a command and arguments (greatly simplified): public class Packet { public String Command; public String[] Arguments; } I would like to have be able to convert from Packet to LoginPacket (or any other) based on a check if Packet.Command == "LOGIN". The login packet would not contain any new data members, but only methods for accessing specific arguments. For example: public class LoginPacket : Packet { public String Username { get { return Arguments[0]; } set { Arguments[0] == value; } } public String Password { get { return Arguments[1]; } set { Arguments[1] == value; } } } It would be great if I could run a simple code that would cast from Packet to LoginPacket with something like LoginPacket _Login = (LoginPacket)_Packet;, but that throws a System.InvalidCastException. It seems like this would be an easy task, as no new data is included, but I can't figure out any other way than copying everything from the Packet class to a new LoginPacket class.

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  • ICMP Redirect Theory VS. Application

    - by joeqwerty
    I'm trying to watch ICMP redirects in a lab using Cisco Packet Tracer (version 5.3.2) and I'm not seeing them, which leads me to believe that either my lab configuration isn't correct or my understanding of ICMP redirects isn't correct or that Packet Tracer doesn't support/use ICMP redirects. Here's what I believe to be true regarding ICMP redirects: Routers send ICMP redirects when all of these conditions are met: The interface on which the packet comes into the router is the same interface on which the packet gets routed out. The subnet or network of the source IP address is on the same subnet or network of the next-hop IP address of the routed packet. The datagram is not source-routed. The router kernel is configured to send redirects. I have the lab set up in Cisco Packet Tracer as displayed in the image and would expect to see an ICMP redirect from Router1 when pinging from PC1 to PC3. I'm not seeing the ICMP redirect and it looks like Router1 is actually routing all of the packets via Router2. I have IP ICMP debugging enabled on Router1 (and Router2) and I'm not seeing any ICMP redirect activity in either console. I'm also not seeing a route to the PC3 network in the routing table on PC1, which I think confirms that the ICMP redirect is not occurring. I'm using only static routing on Routers 1 and 2. Is my understanding of ICMP redirects incorrect, or is there a problem with my lab configuration or does Packet Tracer not support/use ICMP redirects?

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  • How do I fix: The handshake failed due to an unexpected packet format?

    - by Greg Finzer
    I am connecting from Windows Server 2008 R2 to a Linux FTP Server running vsFTPd 2.0.7. I am connecting via SSL. Here is the line of code it is failing on: sslStream = new SslStream(stream, false, CertificateValidation); Here is the log: 220 (vsFTPd 2.0.7) AUTH SSL 234 Proceed with negotiation. I receive the following error: System.IO.IOException: The handshake failed due to an unexpected packet format. at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest) at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest) at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest) at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult) at KellermanSoftware.NetFtpLibrary.ProxySocket.InitSsl() at KellermanSoftware.NetFtpLibrary.FTP.Connect(Boolean implicitConnection)

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  • How to fake source ip-address of a udp-packet?

    - by youllknow
    Hi everyone! Think about the following: Your ISP offers you a dynamic ip-address (for example 123.123.123.123). My question is simple (the answer may not): Is it possible to send a single udp-packet with a outer source-ip (for example 124.124.124.124) to a fixed-ip server? I don't need to get a answer from the server. I just want to know if/how this one way communication can be done, using a faked source-ip address. I'm sorry for my bad English! Thanks for you help in advance!

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  • How do I determine if a packet is RTP/RTCP?

    - by Chris Holmes
    I am using SharpPCap which is built on WinPCap to capture UDP traffic. My end goal is to capture the audio data from H.323 and save those phone conversations as WAV files. But first thing is first - I need to figure out what my UDP packets are crossing the NIC. SharpPCap provides a UdpPacket class that gives me access to the PayloadData of the message. But I am unsure what do with this data. It's a Byte[] array and I don't know how to go about determining if it's an RTP or RTCP packet. I've Googled this topic but there isn't much out there. Any help is appreciated.

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  • Can't get the L2TP IPSEC up and running

    - by Maciej Swic
    i have an Ubuntu 11.10 (oneiric) server running on a ReadyNAS. Im planning to use this to accept ipsec+l2tp connections through a router. However, the connection is failing somewhere half through. Using Openswan IPsec U2.6.28/K3.0.0-12-generic and trying to connect with an iOS 5 iPhone 4S. This is how far i can get: auth.log: Jan 19 13:54:11 ubuntu pluto[1990]: added connection description "PSK" Jan 19 13:54:11 ubuntu pluto[1990]: added connection description "L2TP-PSK-NAT" Jan 19 13:54:11 ubuntu pluto[1990]: added connection description "L2TP-PSK-noNAT" Jan 19 13:54:11 ubuntu pluto[1990]: added connection description "passthrough-for-non-l2tp" Jan 19 13:54:11 ubuntu pluto[1990]: listening for IKE messages Jan 19 13:54:11 ubuntu pluto[1990]: NAT-Traversal: Trying new style NAT-T Jan 19 13:54:11 ubuntu pluto[1990]: NAT-Traversal: ESPINUDP(1) setup failed for new style NAT-T family IPv4 (errno=19) Jan 19 13:54:11 ubuntu pluto[1990]: NAT-Traversal: Trying old style NAT-T Jan 19 13:54:11 ubuntu pluto[1990]: adding interface eth0/eth0 192.168.19.99:500 Jan 19 13:54:11 ubuntu pluto[1990]: adding interface eth0/eth0 192.168.19.99:4500 Jan 19 13:54:11 ubuntu pluto[1990]: adding interface lo/lo 127.0.0.1:500 Jan 19 13:54:11 ubuntu pluto[1990]: adding interface lo/lo 127.0.0.1:4500 Jan 19 13:54:11 ubuntu pluto[1990]: adding interface lo/lo ::1:500 Jan 19 13:54:11 ubuntu pluto[1990]: adding interface eth0/eth0 2001:470:28:81:a00:27ff:* Jan 19 13:54:11 ubuntu pluto[1990]: loading secrets from "/etc/ipsec.secrets" Jan 19 13:54:11 ubuntu pluto[1990]: loading secrets from "/var/lib/openswan/ipsec.secrets.inc" Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: received Vendor ID payload [RFC 3947] method set to=109 Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike] method set to=110 Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: ignoring unknown Vendor ID payload [8f8d83826d246b6fc7a8a6a428c11de8] Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: ignoring unknown Vendor ID payload [439b59f8ba676c4c7737ae22eab8f582] Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: ignoring unknown Vendor ID payload [4d1e0e136deafa34c4f3ea9f02ec7285] Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: ignoring unknown Vendor ID payload [80d0bb3def54565ee84645d4c85ce3ee] Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: ignoring unknown Vendor ID payload [9909b64eed937c6573de52ace952fa6b] Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-03] meth=108, but already using method 110 Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-02] meth=107, but already using method 110 Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-02_n] meth=106, but already using method 110 Jan 19 14:04:31 ubuntu pluto[1990]: packet from 95.*.*.233:500: received Vendor ID payload [Dead Peer Detection] Jan 19 14:04:31 ubuntu pluto[1990]: "PSK"[1] 95.*.*.233 #1: responding to Main Mode from unknown peer 95.*.*.233 Jan 19 14:04:31 ubuntu pluto[1990]: "PSK"[1] 95.*.*.233 #1: transition from state STATE_MAIN_R0 to state STATE_MAIN_R1 Jan 19 14:04:31 ubuntu pluto[1990]: "PSK"[1] 95.*.*.233 #1: STATE_MAIN_R1: sent MR1, expecting MI2 Jan 19 14:04:33 ubuntu pluto[1990]: "PSK"[1] 95.*.*.233 #1: NAT-Traversal: Result using draft-ietf-ipsec-nat-t-ike (MacOS X): both are NATed Jan 19 14:04:33 ubuntu pluto[1990]: "PSK"[1] 95.*.*.233 #1: transition from state STATE_MAIN_R1 to state STATE_MAIN_R2 Jan 19 14:04:33 ubuntu pluto[1990]: "PSK"[1] 95.*.*.233 #1: STATE_MAIN_R2: sent MR2, expecting MI3 Jan 19 14:05:03 ubuntu pluto[1990]: ERROR: asynchronous network error report on eth0 (sport=500) for message to 95.*.*.233 port 500, complainant 95.*.*.233: Connection refused [errno 111, origin ICMP type 3 code 3 (not authenticated)] Router config UDP 500, 1701 and 4500 forwarded to 192.168.19.99 (Ubuntu server for ipsec). Ipsec passthrough enabled. /etc/ipsec.conf # /etc/ipsec.conf - Openswan IPsec configuration file # This file: /usr/share/doc/openswan/ipsec.conf-sample # # Manual: ipsec.conf.5 version 2.0 # conforms to second version of ipsec.conf specification config setup nat_traversal=yes #charonstart=yes #plutostart=yes protostack=netkey conn PSK authby=secret forceencaps=yes pfs=no auto=add keyingtries=3 dpdtimeout=60 dpdaction=clear rekey=no left=192.168.19.99 leftnexthop=192.168.19.1 leftprotoport=17/1701 right=%any rightprotoport=17/%any rightsubnet=vhost:%priv,%no dpddelay=10 #dpdtimeout=10 #dpdaction=clear include /etc/ipsec.d/l2tp-psk.conf /etc/ipsec.d/l2tp-psk.conf conn L2TP-PSK-NAT rightsubnet=vhost:%priv also=L2TP-PSK-noNAT conn L2TP-PSK-noNAT # # PreSharedSecret needs to be specified in /etc/ipsec.secrets as # YourIPAddress %any: "sharedsecret" authby=secret pfs=no auto=add keyingtries=3 # we cannot rekey for %any, let client rekey rekey=no # Set ikelifetime and keylife to same defaults windows has ikelifetime=8h keylife=1h # l2tp-over-ipsec is transport mode type=transport # left=192.168.19.99 # # For updated Windows 2000/XP clients, # to support old clients as well, use leftprotoport=17/%any leftprotoport=17/1701 # # The remote user. # right=%any # Using the magic port of "0" means "any one single port". This is # a work around required for Apple OSX clients that use a randomly # high port, but propose "0" instead of their port. rightprotoport=17/%any dpddelay=10 dpdtimeout=10 dpdaction=clear conn passthrough-for-non-l2tp type=passthrough left=192.168.19.99 leftnexthop=192.168.19.1 right=0.0.0.0 rightsubnet=0.0.0.0/0 auto=route /etc/ipsec.secrets include /var/lib/openswan/ipsec.secrets.inc %any %any: PSK "my-key" 192.168.19.99 %any: PSK "my-key" /etc/xl2tpd/xl2tpd.conf [global] debug network = yes debug tunnel = yes ipsec saref = no listen-addr = 192.168.19.99 [lns default] ip range = 192.168.19.201-192.168.19.220 local ip = 192.168.19.99 require chap = yes refuse chap = no refuse pap = no require authentication = no ppp debug = yes pppoptfile = /etc/ppp/options.xl2tpd length bit = yes /etc/ppp/options.xl2tpd pcp-accept-local ipcp-accept-remote noccp auth crtscts idle 1800 mtu 1410 mru 1410 defaultroute debug lock proxyarp connect-delay 5000 ipcp-accept-local /etc/ppp/chap-secrets # Secrets for authentication using CHAP # client server secret IP addresses maciekish * my-secret * * maciekish my-secret * I can't seem to find the problem. Other ipsec connections to other hosts work from the network im currently at.

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  • SonicOS Enhanced 5.8.1.2 L2TP VPN Authentication Failed

    - by Dean A. Vassallo
    I have a SonicWall TZ 215 running SonicOS Enhanced 5.8.1.2-6o. I have configured the L2TP VPN using the default crypto suite ESP: 3DES/HMAC SHA1 (IKE). Proposals are as such: IKE (Phase 1) Proposal DH Group: Group 2 Encryption: 3DES Authentication: SHA1 Life Time (seconds): 28800 Ipsec (Phase 2) Proposal Protocol: ESP Encryption: 3DES Authentication: SHA1 Enable Perfect Forward Secrecy DISABLED Life Time (seconds): 28800 When attempting to connect via my Mac OS X client I get an authentication error. It appears to pass the pre-authentication but fails to complete. I am at a complete loss. I reconfigured from scratch multiple times...used simple usernames and passwords to verify this wasn't a miskeyed password issue. I have Here are the logs (noted IP has been removed for privacy): 7/1/13 8:19:05.174 PM pppd[1268]: setup_security_context server port: 0x1503 7/1/13 8:19:05.190 PM pppd[1268]: publish_entry SCDSet() failed: Success! 7/1/13 8:19:05.191 PM pppd[1268]: publish_entry SCDSet() failed: Success! 7/1/13 8:19:05.191 PM pppd[1268]: pppd 2.4.2 (Apple version 727.1.1) started by dean, uid 501 7/1/13 8:19:05.192 PM pppd[1268]: L2TP connecting to server ‘0.0.0.0’ (0.0.0.0)... 7/1/13 8:19:05.193 PM pppd[1268]: IPSec connection started 7/1/13 8:19:05.208 PM racoon[1269]: accepted connection on vpn control socket. 7/1/13 8:19:05.209 PM racoon[1269]: Connecting. 7/1/13 8:19:05.209 PM racoon[1269]: IPSec Phase 1 started (Initiated by me). 7/1/13 8:19:05.209 PM racoon[1269]: IKE Packet: transmit success. (Initiator, Main-Mode message 1). 7/1/13 8:19:05.209 PM racoon[1269]: >>>>> phase change status = Phase 1 started by us 7/1/13 8:19:05.231 PM racoon[1269]: >>>>> phase change status = Phase 1 started by peer 7/1/13 8:19:05.231 PM racoon[1269]: IKE Packet: receive success. (Initiator, Main-Mode message 2). 7/1/13 8:19:05.234 PM racoon[1269]: IKE Packet: transmit success. (Initiator, Main-Mode message 3). 7/1/13 8:19:05.293 PM racoon[1269]: IKE Packet: receive success. (Initiator, Main-Mode message 4). 7/1/13 8:19:05.295 PM racoon[1269]: IKE Packet: transmit success. (Initiator, Main-Mode message 5). 7/1/13 8:19:05.315 PM racoon[1269]: IKEv1 Phase 1 AUTH: success. (Initiator, Main-Mode Message 6). 7/1/13 8:19:05.315 PM racoon[1269]: IKE Packet: receive success. (Initiator, Main-Mode message 6). 7/1/13 8:19:05.315 PM racoon[1269]: IKEv1 Phase 1 Initiator: success. (Initiator, Main-Mode). 7/1/13 8:19:05.315 PM racoon[1269]: IPSec Phase 1 established (Initiated by me). 7/1/13 8:19:06.307 PM racoon[1269]: IPSec Phase 2 started (Initiated by me). 7/1/13 8:19:06.307 PM racoon[1269]: >>>>> phase change status = Phase 2 started 7/1/13 8:19:06.308 PM racoon[1269]: IKE Packet: transmit success. (Initiator, Quick-Mode message 1). 7/1/13 8:19:06.332 PM racoon[1269]: attribute has been modified. 7/1/13 8:19:06.332 PM racoon[1269]: IKE Packet: receive success. (Initiator, Quick-Mode message 2). 7/1/13 8:19:06.332 PM racoon[1269]: IKE Packet: transmit success. (Initiator, Quick-Mode message 3). 7/1/13 8:19:06.333 PM racoon[1269]: IKEv1 Phase 2 Initiator: success. (Initiator, Quick-Mode). 7/1/13 8:19:06.333 PM racoon[1269]: IPSec Phase 2 established (Initiated by me). 7/1/13 8:19:06.333 PM racoon[1269]: >>>>> phase change status = Phase 2 established 7/1/13 8:19:06.333 PM pppd[1268]: IPSec connection established 7/1/13 8:19:07.145 PM pppd[1268]: L2TP connection established. 7/1/13 8:19:07.000 PM kernel[0]: ppp0: is now delegating en0 (type 0x6, family 2, sub-family 3) 7/1/13 8:19:07.146 PM pppd[1268]: Connect: ppp0 <--> socket[34:18] 7/1/13 8:19:08.709 PM pppd[1268]: MS-CHAPv2 mutual authentication failed. 7/1/13 8:19:08.710 PM pppd[1268]: Connection terminated. 7/1/13 8:19:08.710 PM pppd[1268]: L2TP disconnecting... 7/1/13 8:19:08.711 PM pppd[1268]: L2TP disconnected 7/1/13 8:19:08.711 PM racoon[1269]: IPSec disconnecting from server 0.0.0.0 7/1/13 8:19:08.711 PM racoon[1269]: IKE Packet: transmit success. (Information message). 7/1/13 8:19:08.712 PM racoon[1269]: IKEv1 Information-Notice: transmit success. (Delete IPSEC-SA). 7/1/13 8:19:08.712 PM racoon[1269]: IKE Packet: transmit success. (Information message). 7/1/13 8:19:08.712 PM racoon[1269]: IKEv1 Information-Notice: transmit success. (Delete ISAKMP-SA). 7/1/13 8:19:08.713 PM racoon[1269]: glob found no matches for path "/var/run/racoon/*.conf" 7/1/13 8:19:08.714 PM racoon[1269]: pfkey DELETE failed: No such file or directory

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  • How to detect generation loss of a transcoded audio.

    - by The Rook
    Lets say you have a 96 kbit mp3 and you Transcode the file into a 320 kbit mp3. How could you programmatically detect the original bit rate or quality? Generation loss is created because each time a lossy algorithm is applied new information will be deemed "unnecessary" and is discarded. How could an algorithm use this property to detect the transcoding of audio. 128 kbps LAME mp3 transcoded to 320 kbps LAME mp3 (I Feel You, Depeche Mode) 10.8 MB. This image was taken from the bottom of this site. The 2 tracks above look nearly identical, but the difference is enough to support this argument.

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  • How to measure productivity loss from slow PCs running Visual Studio?

    - by sunpech
    Many PCs we have on the development team are out-dated and are very slow to run Visual Studio 2008. They should very much be replaced with newer machines. But there's a general reluctance on management/company to buy new machines. How do we come up with numbers and benchmarks to show that these slow PCs are causing a loss in productivity? Obviously we can't call them to sit down with us as we build solutions and/or open various files. Is there an objective way to come up with some kind of reliable numbers that non-technical people can understand? It'd be nice to have a way to measure this across an entire organization on many different PCs running Visual Studio. I'm looking for an answer that does better than using a physical stopwatch. :)

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