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  • iptables drop packet by hex string match

    - by Flint
    I got this packet captured with tcpdump but I'm not sure how to use the --hex-string param to match the packet. Can someone show me how to do it? 11:18:26.614537 IP (tos 0x0, ttl 17, id 19245, offset 0, flags [DF], proto UDP (17), length 37) x.x.187.207.1234 > x.x.152.202.6543: [no cksum] UDP, length 9 0x0000: f46d 0425 b202 000a b853 22cc 0800 4500 .m.%.....S"...E. 0x0010: 0025 4b2d 4000 1111 0442 5ebe bbcf 6701 .%[email protected]^...g. 0x0020: 98ca 697d 6989 0011 0000 ffff ffff 5630 ..i}i.........V0 0x0030: 3230 3300 0000 0000 0000 0000 203.........

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  • Iptables mark incoming packet - vpn routing

    - by Tom
    I have connected my home to my workplace for out of house backup reasons through openvpn. The connection is working nicely. At work I have 5 fixed IP addresses. Now I would like to assign one of these IP addresses to be forwarded to my home machine. I have confirmed packet arrival at my home machine with tcpdump. The problem is that my default route at home is NOT the tun0 (naturally), but eth0 to my own ISP. So I created a separate routing table to route my tun0 packets back to where they belong, but do not how to mark the incoming packet which arrive through tun0 with iptables, so I can drive them back. I do not want any port restrictions, but only what comes from tun0 should leave through tun0 thanks tom

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  • Library like ENet, but for TCP?

    - by Milo
    I'm not looking to use boost::asio, it is overly complex for my needs. I'm building a game that is cross platform, for desktop, iPhone and Android. I found a library called ENet which is pretty much what I need, but it uses UDP which does not seem to support encryption and a few other things. Given that the game is an event driven card game, TCP seems like the right fit. However, all I have found is WINSOCK / berkley sockets and bost::asio. Here is a sample client server application with ENet: #include <enet/enet.h> #include <stdlib.h> #include <string> #include <iostream> class Host { ENetAddress address; ENetHost * server; ENetHost* client; ENetEvent event; public: Host() :server(NULL) { enet_initialize(); setupServer(); } void setupServer() { if(server) { enet_host_destroy(server); server = NULL; } address.host = ENET_HOST_ANY; /* Bind the server to port 1234. */ address.port = 1721; server = enet_host_create (& address /* the address to bind the server host to */, 32 /* allow up to 32 clients and/or outgoing connections */, 2 /* allow up to 2 channels to be used, 0 and 1 */, 0 /* assume any amount of incoming bandwidth */, 0 /* assume any amount of outgoing bandwidth */); } void daLoop() { while(true) { /* Wait up to 1000 milliseconds for an event. */ while (enet_host_service (server, & event, 5000) > 0) { ENetPacket * packet; switch (event.type) { case ENET_EVENT_TYPE_CONNECT: printf ("A new client connected from %x:%u.\n", event.peer -> address.host, event.peer -> address.port); /* Store any relevant client information here. */ event.peer -> data = "Client information"; /* Create a reliable packet of size 7 containing "packet\0" */ packet = enet_packet_create ("packet", strlen ("packet") + 1, ENET_PACKET_FLAG_RELIABLE); /* Extend the packet so and append the string "foo", so it now */ /* contains "packetfoo\0" */ enet_packet_resize (packet, strlen ("packetfoo") + 1); strcpy ((char*)& packet -> data [strlen ("packet")], "foo"); /* Send the packet to the peer over channel id 0. */ /* One could also broadcast the packet by */ /* enet_host_broadcast (host, 0, packet); */ enet_peer_send (event.peer, 0, packet); /* One could just use enet_host_service() instead. */ enet_host_flush (server); break; case ENET_EVENT_TYPE_RECEIVE: printf ("A packet of length %u containing %s was received from %s on channel %u.\n", event.packet -> dataLength, event.packet -> data, event.peer -> data, event.channelID); /* Clean up the packet now that we're done using it. */ enet_packet_destroy (event.packet); break; case ENET_EVENT_TYPE_DISCONNECT: printf ("%s disconected.\n", event.peer -> data); /* Reset the peer's client information. */ event.peer -> data = NULL; } } } } ~Host() { if(server) { enet_host_destroy(server); server = NULL; } atexit (enet_deinitialize); } }; class Client { ENetAddress address; ENetEvent event; ENetPeer *peer; ENetHost* client; public: Client() :peer(NULL) { enet_initialize(); setupPeer(); } void setupPeer() { client = enet_host_create (NULL /* create a client host */, 1 /* only allow 1 outgoing connection */, 2 /* allow up 2 channels to be used, 0 and 1 */, 57600 / 8 /* 56K modem with 56 Kbps downstream bandwidth */, 14400 / 8 /* 56K modem with 14 Kbps upstream bandwidth */); if (client == NULL) { fprintf (stderr, "An error occurred while trying to create an ENet client host.\n"); exit (EXIT_FAILURE); } /* Connect to some.server.net:1234. */ enet_address_set_host (& address, "192.168.2.13"); address.port = 1721; /* Initiate the connection, allocating the two channels 0 and 1. */ peer = enet_host_connect (client, & address, 2, 0); if (peer == NULL) { fprintf (stderr, "No available peers for initiating an ENet connection.\n"); exit (EXIT_FAILURE); } /* Wait up to 5 seconds for the connection attempt to succeed. */ if (enet_host_service (client, & event, 20000) > 0 && event.type == ENET_EVENT_TYPE_CONNECT) { std::cout << "Connection to some.server.net:1234 succeeded." << std::endl; } else { /* Either the 5 seconds are up or a disconnect event was */ /* received. Reset the peer in the event the 5 seconds */ /* had run out without any significant event. */ enet_peer_reset (peer); puts ("Connection to some.server.net:1234 failed."); } } void daLoop() { ENetPacket* packet; /* Create a reliable packet of size 7 containing "packet\0" */ packet = enet_packet_create ("backet", strlen ("backet") + 1, ENET_PACKET_FLAG_RELIABLE); /* Extend the packet so and append the string "foo", so it now */ /* contains "packetfoo\0" */ enet_packet_resize (packet, strlen ("backetfoo") + 1); strcpy ((char*)& packet -> data [strlen ("backet")], "foo"); /* Send the packet to the peer over channel id 0. */ /* One could also broadcast the packet by */ /* enet_host_broadcast (host, 0, packet); */ enet_peer_send (event.peer, 0, packet); /* One could just use enet_host_service() instead. */ enet_host_flush (client); while(true) { /* Wait up to 1000 milliseconds for an event. */ while (enet_host_service (client, & event, 1000) > 0) { ENetPacket * packet; switch (event.type) { case ENET_EVENT_TYPE_RECEIVE: printf ("A packet of length %u containing %s was received from %s on channel %u.\n", event.packet -> dataLength, event.packet -> data, event.peer -> data, event.channelID); /* Clean up the packet now that we're done using it. */ enet_packet_destroy (event.packet); break; } } } } ~Client() { atexit (enet_deinitialize); } }; int main() { std::string a; std::cin >> a; if(a == "host") { Host host; host.daLoop(); } else { Client c; c.daLoop(); } return 0; } I looked at some socket tutorials and they seemed a bit too low level. I just need something that abstracts away the platform (eg, no WINSOCKS) and that has basic ability to keep track of connected clients and send them messages. Thanks

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  • What happens after a packet is captured?

    - by Rayne
    Hi all, I've been reading about what happens after packets are captured by NICs, and the more I read, the more I'm confused. Firstly, I've read that traditionally, after a packet is captured by the NIC, it gets copied to a block of memory in the kernel space, then to the user space for whatever application that then works on the packet data. Then I read about DMA, where the NIC directly copies the packet into memory, bypassing the CPU. So is the NIC - kernel memory - User space memory flow still valid? Also, do most NIC (e.g. Myricom) use DMA to improve packet capture rates? Secondly, does RSS (Receive Side Scaling) work similarly in both Windows and Linux systems? I can only find detailed explanations on how RSS works in MSDN articles, where they talk about how RSS (and MSI-X) works on Windows Server 2008. But the same concept of RSS and MSI-X should still apply for linux systems, right? Thank you. Regards, Rayne

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  • Packet Crafting on a Mac

    - by JayCrossler
    I think (based on searching the forums), that NetCat is the best option, but wanted to hear if others are preferable. Anyone have good success with a packet-crafting tool (specifically on Mac)? I've tried HPing, but had some issues. I'm looking into NetCat ('nc' on mac) now, but it's not working as I had thought. Basically, I captured some packets that a remote control sends over a wifi network to turn lights on and off (using X10 controllers), and am looking for a way to replay them by crafting a TCP packet from the command line. I used Wireshark to sniff the traffic, so I know the package is: DEVICE -sendplc-"C4 DIM 10" I'm trying: echo 'DEVICE -sendplc-"C4 DIM 10"' nc 192.168.2.196 6003 but there's no response from the receiving system. The exact bytestream is (if anyone wants to check that I got the right dataframe): 08004642f1b400260897ad6308004500004b08e240004006aaf5c0a802c1c0a802c4d8d7177399aab39 e57ff4753801880ae37ea00000101080a323353ce01b406424445564943457e73656e64706c637e2243 34204f4e220a Next step I'm going to check is to make sure the packet arrives exactly by sniffing and compare it to the original. [EDIT: Also at ServerFault now: Packet Crafting on a Mac, so this one becomes a duplicate across the two sites]

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  • What Libs should i use to write a packet sniffer in perl

    - by Mouseroot
    I basicly want to write a small packet sniffer in perl im using ubuntu 9 im basically looking to sniff all packets on my nic and return data such as source and destination address as well as the data i looked into Net::Write::Layer2 but i could never get it to run as it says it cannot find the required libs and i cannot find the dependents adn that lib is for writeing data and not accepting it ive read that i should use libpcap but no good examples are available i basicly just need to know what lib i should use and ill find a example/tutorial on using said lib Thanks in Advance

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  • packet mmap send packet format

    - by SeregASM
    I want to improve packet transmitting performance. Before that I used raw sockets and now I study packet_mmap. I have packets(frames) which I already captured from kernel module from another PC, put to current PC and now I want to retransmit them to local interface with following forwarding. I have got example of packet_mmap, integrated it to my project, but I send fd_socket = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); memset(&my_addr, 0, sizeof(struct sockaddr_ll)); my_addr.sll_family = PF_PACKET; my_addr.sll_protocol = htons(ETH_P_ALL); strcpy(str_devname, "eth0"); strncpy(s_ifr.ifr_name, str_devname, sizeof(s_ifr.ifr_name)); ec = ioctl(fd_socket, SIOCGIFINDEX, &s_ifr); i_ifindex = s_ifr.ifr_ifindex; memset(&my_addr, 0, sizeof(struct sockaddr_ll)); my_addr.sll_family = AF_PACKET; my_addr.sll_protocol = ETH_P_ALL; my_addr.sll_ifindex = i_ifindex; bind(fd_socket, (struct sockaddr *) &my_addr, sizeof(struct sockaddr_ll) s_packet_req.tp_block_size = c_buffer_sz; s_packet_req.tp_frame_size = c_buffer_sz; s_packet_req.tp_block_nr = c_buffer_nb; s_packet_req.tp_frame_nr = c_buffer_nb; size = s_packet_req.tp_block_size * s_packet_req.tp_block_nr; if (setsockopt(fd_socket, SOL_PACKET, PACKET_TX_RING, (char *) &s_packet_req, sizeof(s_packet_req)) < 0) { perror("setsockopt: PACKET_TX_RING"); return; } if (c_sndbuf_sz) { printf("send buff size = %d\n", c_sndbuf_sz); if (setsockopt(fd_socket, SOL_SOCKET, SO_SNDBUF, &c_sndbuf_sz, sizeof(c_sndbuf_sz)) < 0){ perror("getsockopt: SO_SNDBUF"); exit(1); } } data_offset = TPACKET_HDRLEN - sizeof(struct sockaddr_ll); printf("data offset = %d bytes\n", data_offset); ps_header_start = (tpacket_hdr *) mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd_socket, 0); if (ps_header_start == (void*) -1) { perror("mmap"); exit(1); } Then I fill data ps_header = ((struct tpacket_hdr *) ((char *) ps_header_start + (c_buffer_sz * i_index))); if (!ps_header) { perror("ps_header") ; return NULL; } data = ((char*) ps_header) + data_offset; switch ((volatile uint32_t) ps_header->tp_status) { case TP_STATUS_AVAILABLE: printf("TP_STATUS_AVAILABLE, index=%d\n",i_index) ; memcpy(data, packet_data, size); pthread_mutex_lock(&index_locker) ; i_index++; pthread_mutex_unlock(&index_locker) ; if (i_index >= c_buffer_nb) { i_index = 0; first_loop = 0; } /* update packet len */ ps_header->tp_len = size; /* set header flag to USER (trigs xmit)*/ ps_header->tp_status = TP_STATUS_SEND_REQUEST; then I send ec_send = sendto(fd_socket, NULL, 0, 0, (struct sockaddr *) ps_sockaddr, sizeof(struct sockaddr_ll)); I have got no errors, ec_send=not null size of sended data. But there are no data routed to destination host. So, I ask - what data I should pass to ring buffer, now I include headers ip,tcp, should I include MAC header? - May be I have to set additional flags to route my packets.

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  • Linux Kernel Packet Forwarding Performance

    - by Bob Somers
    I've been using a Linux box as a router for some time now. Nothing too fancy, just enabling forwarding in the kernel, turning on masquerading, and setting up iptables to poke a few holes in the firewall. Recently a friend of mine pointed out a performance problem. Single TCP connections seem to experience very poor performance. You have to open multiple parallel TCP connections to get decent speed. For example, I have a 10 Mbit internet connection. When I download a file from a known-fast source using something like the DownThemAll! extension for Firefox (which opens multiple parallel TCP connections) I can get it to max out my downstream bandwidth at around 1 MB/s. However, when I download the same file using the built-in download manager in Firefox (uses only a single TCP connection) it starts fast and the speed tanks until it tops out around 100 KB/s to 350 KB/s. I've checked the internal network and it doesn't seem to have any problems. Everything goes through a 100 Mbit switch. I've also run iperf both internally (from the router to my desktop) and externally (from my desktop to a Linux box I own out on the net) and haven't seen any problems. It tops out around 1 MB/s like it should. Speedtest.net also reports 10 Mbits speeds. The load on the Linux machine is around 0.00, 0.00, 0.00 all the time, and it's got plenty of free RAM. It's an older laptop with a Pentium M 1.6 GHz processor and 1 GB of RAM. The internal network is connected to the built in Intel NIC and the cable modem is connected to a Netgear FA511 32-bit PCMCIA network card. I think the problem is with the packet forwarding in the router, but I honestly am not sure where the problem could be. Is there anything that would substantially slow down a single TCP stream?

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  • Unusable network, packet losses between router and NIC

    - by KáGé
    I have this setup: Gigabyte P35-DS3P motherboard Asus NX1101 PCI network card (the one on the motherboard got fried a few years ago by a power surge) Asus RT-N16 router Windows 7 x64 I think the other specs are irrelevant here, but I'll post them if you say so. Until a week ago everything was fine, but then my network became unusable: websites start loading but timeout before anything would come through (true for the web interface of the router as well), I can't reach the computer from my notebook and Windows' ping utility measures a ~50% packet loss between the computer and the router. Pinging localhost is good. The router works completely fine when wired to my notebook. I also tested different ports on the router, different cables, different router and connecting directly to the modem, but it's still the same. Sometimes it works for a few minutes right after turning on the machine, but then it becomes crap again, but mostly it's useless from the start. I've tried updating the firmware on the router, updating the driver for the network card (after which I started getting BSoDs in every 15 minutes), reinstalling Windows, swapping to Fedora 15 but none of them changed anything. Does this mean that the network card is dying, or could it be something else? If it's the card, what model do you recommend as a replacement? (Could be PCI or PCI-Ex x1) Thanks for your help.

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  • unexplainable packet drops with 5 ethernet NICs and low traffic on Ubuntu

    - by jon
    I'm stuck on problem where my machine started to drops packets with no sign of ANY system load or high interrupt usage after an upgrade to Ubuntu 12.04. My server is a network monitoring sensor, running Ubuntu LTS 12.04, it passively collects packets from 5 interfaces doing network intrusion type stuff. Before the upgrade I managed to collect 200+GB of packets a day while writing them to disk with around 0% packet loss depending on the day with the help of CPU affinity and NIC IRQ to CPU bindings. Now I lose a great deal of packets with none of my applications running and at very low PPS rate which a modern workstation NIC would have no trouble with. Specs: x64 Xeon 4 cores 3.2 Ghz 16 GB RAM NICs: 5 Intel Pro NICs using the e1000 driver (NAPI). [1] eth0 and eth1 are integrated NICs (in the motherboard) There are 2 other PCI-X network cards, each with 2 Ethernet ports. 3 of the interfaces are running at Gigabit Ethernet, the others are not because they're attached to hubs. Specs: [2] http://support.dell.com/support/edocs/systems/pe2850/en/ug/t1390aa.htm uptime 17:36:00 up 1:43, 2 users, load average: 0.00, 0.01, 0.05 # uname -a Linux nms 3.2.0-29-generic #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux I also have the CPU governor set to performance mode and irqbalance off. The problem still occurs with them on. # lspci -t -vv -[0000:00]-+-00.0 Intel Corporation E7520 Memory Controller Hub +-02.0-[01-03]--+-00.0-[02]----0e.0 Dell PowerEdge Expandable RAID controller 4 | \-00.2-[03]-- +-04.0-[04]-- +-05.0-[05-07]--+-00.0-[06]----07.0 Intel Corporation 82541GI Gigabit Ethernet Controller | \-00.2-[07]----08.0 Intel Corporation 82541GI Gigabit Ethernet Controller +-06.0-[08-0a]--+-00.0-[09]--+-04.0 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) | | \-04.1 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) | \-00.2-[0a]--+-02.0 Digium, Inc. Wildcard TE210P/TE212P dual-span T1/E1/J1 card 3.3V | +-03.0 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) | \-03.1 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) +-1d.0 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB UHCI Controller #1 +-1d.1 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB UHCI Controller #2 +-1d.2 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB UHCI Controller #3 +-1d.7 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB2 EHCI Controller +-1e.0-[0b]----0d.0 Advanced Micro Devices [AMD] nee ATI RV100 QY [Radeon 7000/VE] +-1f.0 Intel Corporation 82801EB/ER (ICH5/ICH5R) LPC Interface Bridge \-1f.1 Intel Corporation 82801EB/ER (ICH5/ICH5R) IDE Controller I believe the NIC nor the NIC drivers are dropping the packets because ethtool reports 0 under rx_missed_errors and rx_no_buffer_count for each interface. On the old system, if it couldn't keep up this is where the drops would be. I drop packets on multiple interfaces just about every second, usually in small increments of 2-4. I tried all these sysctl values, I'm currently using the uncommented ones. # cat /etc/sysctl.conf # high net.core.netdev_max_backlog = 3000000 net.core.rmem_max = 16000000 net.core.rmem_default = 8000000 # defaults #net.core.netdev_max_backlog = 1000 #net.core.rmem_max = 131071 #net.core.rmem_default = 163480 # moderate #net.core.netdev_max_backlog = 10000 #net.core.rmem_max = 33554432 #net.core.rmem_default = 33554432 Here's an example of an interface stats report with ethtool. They are all the same, nothing is out of the ordinary ( I think ), so I'm only going to show one: ethtool -S eth2 NIC statistics: rx_packets: 7498 tx_packets: 0 rx_bytes: 2722585 tx_bytes: 0 rx_broadcast: 327 tx_broadcast: 0 rx_multicast: 1504 tx_multicast: 0 rx_errors: 0 tx_errors: 0 tx_dropped: 0 multicast: 1504 collisions: 0 rx_length_errors: 0 rx_over_errors: 0 rx_crc_errors: 0 rx_frame_errors: 0 rx_no_buffer_count: 0 rx_missed_errors: 0 tx_aborted_errors: 0 tx_carrier_errors: 0 tx_fifo_errors: 0 tx_heartbeat_errors: 0 tx_window_errors: 0 tx_abort_late_coll: 0 tx_deferred_ok: 0 tx_single_coll_ok: 0 tx_multi_coll_ok: 0 tx_timeout_count: 0 tx_restart_queue: 0 rx_long_length_errors: 0 rx_short_length_errors: 0 rx_align_errors: 0 tx_tcp_seg_good: 0 tx_tcp_seg_failed: 0 rx_flow_control_xon: 0 rx_flow_control_xoff: 0 tx_flow_control_xon: 0 tx_flow_control_xoff: 0 rx_long_byte_count: 2722585 rx_csum_offload_good: 0 rx_csum_offload_errors: 0 alloc_rx_buff_failed: 0 tx_smbus: 0 rx_smbus: 0 dropped_smbus: 01 # ifconfig eth0 Link encap:Ethernet HWaddr 00:11:43:e0:e2:8c UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:373348 errors:16 dropped:95 overruns:0 frame:16 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:356830572 (356.8 MB) TX bytes:0 (0.0 B) eth1 Link encap:Ethernet HWaddr 00:11:43:e0:e2:8d UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:13616 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:8690528 (8.6 MB) TX bytes:0 (0.0 B) eth2 Link encap:Ethernet HWaddr 00:04:23:e1:77:6a UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:7750 errors:0 dropped:471 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2780935 (2.7 MB) TX bytes:0 (0.0 B) eth3 Link encap:Ethernet HWaddr 00:04:23:e1:77:6b UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:5112 errors:0 dropped:206 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:639472 (639.4 KB) TX bytes:0 (0.0 B) eth4 Link encap:Ethernet HWaddr 00:04:23:b6:35:6c UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:961467 errors:0 dropped:935 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:958561305 (958.5 MB) TX bytes:0 (0.0 B) eth5 Link encap:Ethernet HWaddr 00:04:23:b6:35:6d inet addr:192.168.1.6 Bcast:192.168.1.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:4264 errors:0 dropped:16 overruns:0 frame:0 TX packets:699 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:572228 (572.2 KB) TX bytes:124456 (124.4 KB) I tried the defaults, then started to play around with settings. I wasn't using any flow control and I increased the RxDescriptor count to 4096 before the upgrade as well without any problems. # cat /etc/modprobe.d/e1000.conf options e1000 XsumRX=0,0,0,0,0 RxDescriptors=4096,4096,4096,4096,4096 FlowControl=0,0,0,0,0 debug=16 Here's my network configuration file, I turned off checksumming and various offloading mechanisms along with setting CPU affinity with heavy use interfaces getting an entire CPU and light use interfaces sharing a CPU. I used these settings prior to the upgrade without problems. # cat /etc/network/interfaces # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface eth0 inet manual pre-up /sbin/ethtool -G eth0 rx 4096 tx 0 pre-up /sbin/ethtool -K eth0 gro off gso off rx off pre-up /sbin/ethtool -A eth0 rx off autoneg off up ifconfig eth0 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "4" > /proc/irq/48/smp_affinity down ifconfig eth0 down post-down /sbin/ethtool -G eth0 rx 256 tx 256 post-down /sbin/ethtool -K eth0 gro on gso on rx on post-down /sbin/ethtool -A eth0 rx on autoneg on auto eth1 iface eth1 inet manual pre-up /sbin/ethtool -G eth1 rx 4096 tx 0 pre-up /sbin/ethtool -K eth1 gro off gso off rx off pre-up /sbin/ethtool -A eth1 rx off autoneg off up ifconfig eth1 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "4" > /proc/irq/49/smp_affinity down ifconfig eth1 down post-down /sbin/ethtool -G eth1 rx 256 tx 256 post-down /sbin/ethtool -K eth1 gro on gso on rx on post-down /sbin/ethtool -A eth1 rx on autoneg on auto eth2 iface eth2 inet manual pre-up /sbin/ethtool -G eth2 rx 4096 tx 0 pre-up /sbin/ethtool -K eth2 gro off gso off rx off pre-up /sbin/ethtool -A eth2 rx off autoneg off up ifconfig eth2 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "1" > /proc/irq/82/smp_affinity down ifconfig eth2 down post-down /sbin/ethtool -G eth2 rx 256 tx 256 post-down /sbin/ethtool -K eth2 gro on gso on rx on post-down /sbin/ethtool -A eth2 rx on autoneg on auto eth3 iface eth3 inet manual pre-up /sbin/ethtool -G eth3 rx 4096 tx 0 pre-up /sbin/ethtool -K eth3 gro off gso off rx off pre-up /sbin/ethtool -A eth3 rx off autoneg off up ifconfig eth3 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "2" > /proc/irq/83/smp_affinity down ifconfig eth3 down post-down /sbin/ethtool -G eth3 rx 256 tx 256 post-down /sbin/ethtool -K eth3 gro on gso on rx on post-down /sbin/ethtool -A eth3 rx on autoneg on auto eth4 iface eth4 inet manual pre-up /sbin/ethtool -G eth4 rx 4096 tx 0 pre-up /sbin/ethtool -K eth4 gro off gso off rx off pre-up /sbin/ethtool -A eth4 rx off autoneg off up ifconfig eth4 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "4" > /proc/irq/77/smp_affinity down ifconfig eth4 down post-down /sbin/ethtool -G eth4 rx 256 tx 256 post-down /sbin/ethtool -K eth4 gro on gso on rx on post-down /sbin/ethtool -A eth4 rx on autoneg on auto eth5 iface eth5 inet static pre-up /etc/fw.conf address 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255 gateway 192.168.1.1 dns-nameservers 192.168.1.2 192.168.1.3 up ifconfig eth5 up post-up echo "8" > /proc/irq/77/smp_affinity down ifconfig eth5 down Here's a few examples of packet drops, i ran one after another, probabling totaling 3 or 4 seconds. You can see increases in the drops from the 1st and 3rd. This was a non-busy time, very little traffic. # awk '{ print $1,$5 }' /proc/net/dev Inter-| face drop eth3: 225 lo: 0 eth2: 505 eth1: 0 eth5: 17 eth0: 105 eth4: 1034 # awk '{ print $1,$5 }' /proc/net/dev Inter-| face drop eth3: 225 lo: 0 eth2: 507 eth1: 0 eth5: 17 eth0: 105 eth4: 1034 # awk '{ print $1,$5 }' /proc/net/dev Inter-| face drop eth3: 227 lo: 0 eth2: 512 eth1: 0 eth5: 17 eth0: 105 eth4: 1039 I tried the pci=noacpi options. With and without, it's the same. This is what my interrupt stats looked like before the upgrade, after, with ACPI on PCI it showed multiple NICs bound to an interrupt and shared with other devices such as USB drives which I didn't like so I think i'm going to keep it with ACPI off as it's easier to designate sole purpose interrupts. Is there any advantage I would have using the default i.e. ACPI w/ PCI. ? # cat /etc/default/grub | grep CMD_LINE GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 noacpi pci=noacpi" GRUB_CMDLINE_LINUX="" # cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 0: 45 0 0 16 IO-APIC-edge timer 1: 1 0 0 7936 IO-APIC-edge i8042 2: 0 0 0 0 XT-PIC-XT-PIC cascade 6: 0 0 0 3 IO-APIC-edge floppy 8: 0 0 0 1 IO-APIC-edge rtc0 9: 0 0 0 0 IO-APIC-edge acpi 12: 0 0 0 1809 IO-APIC-edge i8042 14: 1 0 0 4498 IO-APIC-edge ata_piix 15: 0 0 0 0 IO-APIC-edge ata_piix 16: 0 0 0 0 IO-APIC-fasteoi uhci_hcd:usb2 18: 0 0 0 1350 IO-APIC-fasteoi uhci_hcd:usb4, radeon 19: 0 0 0 0 IO-APIC-fasteoi uhci_hcd:usb3 23: 0 0 0 4099 IO-APIC-fasteoi ehci_hcd:usb1 38: 0 0 0 61963 IO-APIC-fasteoi megaraid 48: 0 0 1002319 4 IO-APIC-fasteoi eth0 49: 0 0 38772 3 IO-APIC-fasteoi eth1 77: 0 0 130076 432159 IO-APIC-fasteoi eth4 78: 0 0 0 23917 IO-APIC-fasteoi eth5 82: 1329033 0 0 4 IO-APIC-fasteoi eth2 83: 0 4886525 0 6 IO-APIC-fasteoi eth3 NMI: 5 6 4 5 Non-maskable interrupts LOC: 61409 57076 64257 114764 Local timer interrupts SPU: 0 0 0 0 Spurious interrupts IWI: 0 0 0 0 IRQ work interrupts RES: 17956 25333 13436 14789 Rescheduling interrupts CAL: 22436 607 539 478 Function call interrupts TLB: 1525 1458 4600 4151 TLB shootdowns TRM: 0 0 0 0 Thermal event interrupts THR: 0 0 0 0 Threshold APIC interrupts MCE: 0 0 0 0 Machine check exceptions MCP: 16 16 16 16 Machine check polls ERR: 0 MIS: 0 Here's sample output of vmstat, showing the system. Barebones system right now. root@nms:~# vmstat -S m 1 procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 0 14992 192 1029 0 0 56 2 419 29 1 0 99 0 0 0 0 14992 192 1029 0 0 0 0 922 27 0 0 100 0 0 0 0 14991 192 1029 0 0 0 36 763 50 0 0 100 0 0 0 0 14991 192 1029 0 0 0 0 646 35 0 0 100 0 0 0 0 14991 192 1029 0 0 0 0 722 54 0 0 100 0 0 0 0 14991 192 1029 0 0 0 0 793 27 0 0 100 0 ^C Here's dmesg output. I can't figure out why my PCI-X slots are negotiated as PCI. The network cards are all PCI-X with the exception of the integrated NICs that came with the server. In the output below it looks as if eth3 and eth2 negotiated at PCI-X speeds rather than PCI:66Mhz. Wouldn't they all drop to PCI:66Mhz? If your integrated NICs are PCI, as labeled below (eth0,eth1), then wouldn't all devices on your bus speed drop down to that slower bus speed? If not, I still don't know why only one of my NICs ( each has two ethernet ports) is labeled as PCI-X in the output below. Does that mean it is running at PCI-X speeds are is it showing that it's capable? # dmesg | grep e1000 [ 3678.349337] e1000: Intel(R) PRO/1000 Network Driver - version 7.3.21-k8-NAPI [ 3678.349342] e1000: Copyright (c) 1999-2006 Intel Corporation. [ 3678.349394] e1000 0000:06:07.0: PCI->APIC IRQ transform: INT A -> IRQ 48 [ 3678.409725] e1000 0000:06:07.0: Receive Descriptors set to 4096 [ 3678.409730] e1000 0000:06:07.0: Checksum Offload Disabled [ 3678.409734] e1000 0000:06:07.0: Flow Control Disabled [ 3678.586409] e1000 0000:06:07.0: eth0: (PCI:66MHz:32-bit) 00:11:43:e0:e2:8c [ 3678.586419] e1000 0000:06:07.0: eth0: Intel(R) PRO/1000 Network Connection [ 3678.586642] e1000 0000:07:08.0: PCI->APIC IRQ transform: INT A -> IRQ 49 [ 3678.649854] e1000 0000:07:08.0: Receive Descriptors set to 4096 [ 3678.649859] e1000 0000:07:08.0: Checksum Offload Disabled [ 3678.649863] e1000 0000:07:08.0: Flow Control Disabled [ 3678.826436] e1000 0000:07:08.0: eth1: (PCI:66MHz:32-bit) 00:11:43:e0:e2:8d [ 3678.826444] e1000 0000:07:08.0: eth1: Intel(R) PRO/1000 Network Connection [ 3678.826627] e1000 0000:09:04.0: PCI->APIC IRQ transform: INT A -> IRQ 82 [ 3679.093266] e1000 0000:09:04.0: Receive Descriptors set to 4096 [ 3679.093271] e1000 0000:09:04.0: Checksum Offload Disabled [ 3679.093275] e1000 0000:09:04.0: Flow Control Disabled [ 3679.130239] e1000 0000:09:04.0: eth2: (PCI-X:133MHz:64-bit) 00:04:23:e1:77:6a [ 3679.130246] e1000 0000:09:04.0: eth2: Intel(R) PRO/1000 Network Connection [ 3679.130449] e1000 0000:09:04.1: PCI->APIC IRQ transform: INT B -> IRQ 83 [ 3679.397312] e1000 0000:09:04.1: Receive Descriptors set to 4096 [ 3679.397318] e1000 0000:09:04.1: Checksum Offload Disabled [ 3679.397321] e1000 0000:09:04.1: Flow Control Disabled [ 3679.434350] e1000 0000:09:04.1: eth3: (PCI-X:133MHz:64-bit) 00:04:23:e1:77:6b [ 3679.434360] e1000 0000:09:04.1: eth3: Intel(R) PRO/1000 Network Connection [ 3679.434553] e1000 0000:0a:03.0: PCI->APIC IRQ transform: INT A -> IRQ 77 [ 3679.704072] e1000 0000:0a:03.0: Receive Descriptors set to 4096 [ 3679.704077] e1000 0000:0a:03.0: Checksum Offload Disabled [ 3679.704081] e1000 0000:0a:03.0: Flow Control Disabled [ 3679.738364] e1000 0000:0a:03.0: eth4: (PCI:33MHz:64-bit) 00:04:23:b6:35:6c [ 3679.738371] e1000 0000:0a:03.0: eth4: Intel(R) PRO/1000 Network Connection [ 3679.738538] e1000 0000:0a:03.1: PCI->APIC IRQ transform: INT B -> IRQ 78 [ 3680.046060] e1000 0000:0a:03.1: eth5: (PCI:33MHz:64-bit) 00:04:23:b6:35:6d [ 3680.046067] e1000 0000:0a:03.1: eth5: Intel(R) PRO/1000 Network Connection [ 3682.132415] e1000: eth0 NIC Link is Up 100 Mbps Half Duplex, Flow Control: None [ 3682.224423] e1000: eth1 NIC Link is Up 100 Mbps Half Duplex, Flow Control: None [ 3682.316385] e1000: eth2 NIC Link is Up 100 Mbps Half Duplex, Flow Control: None [ 3682.408391] e1000: eth3 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None [ 3682.500396] e1000: eth4 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None [ 3682.708401] e1000: eth5 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX At first I thought it was the NIC drivers but I'm not so sure. I really have no idea where else to look at the moment. Any help is greatly appreciated as I'm struggling with this. If you need more information just ask. Thanks! [1]http://www.cs.fsu.edu/~baker/devices/lxr/http/source/linux/Documentation/networking/e1000.txt?v=2.6.11.8 [2] http://support.dell.com/support/edocs/systems/pe2850/en/ug/t1390aa.htm

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  • Encoding/Decoding hex packet

    - by Roberto Pulvirenti
    I want to send this hex packet: 00 38 60 dc 00 00 04 33 30 3c 00 00 00 20 63 62 39 62 33 61 36 37 34 64 31 36 66 32 31 39 30 64 30 34 30 63 30 39 32 66 34 66 38 38 32 62 00 06 35 2e 31 33 2e 31 00 00 02 3c so i build the string: string packet = "003860dc0000" + textbox1.text+ "00000020" + textbox2.text+ "0006" + textbox3.text; then "convert" it to ascii: conn_str = HexString2Ascii(packet); then i send the packet... but i have this: 00 38 60 **c3 9c** 00 00 04 33 30 3c 00 00 00 20 63 62 39 62 33 61 36 37 34 64 31 36 66 32 31 39 30 64 30 34 30 63 30 39 32 66 34 66 38 38 32 62 00 06 35 2e 31 33 2e 31 00 00 02 3c **0a** why?? Thank you! P.S. the function is: private string HexString2Ascii(string hexString) { byte[] tmp; int j = 0; int lenght; lenght=hexString.Length-2; tmp = new byte[(hexString.Length)/2]; for (int i = 0; i <= lenght; i += 2) { tmp[j] =(byte)Convert.ToChar(Int32.Parse(hexString.Substring(i, 2), System.Globalization.NumberStyles.HexNumber)); j++; } return Encoding.GetEncoding(1252).GetString(tmp); }

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  • SYN flooding still a threat to servers?

    - by Rob
    Well recently I've been reading about different Denial of Service methods. One method that kind of stuck out was SYN flooding. I'm a member of some not-so-nice forums, and someone was selling a python script that would DoS a server using SYN packets with a spoofed IP address. However, if you sent a SYN packet to a server, with a spoofed IP address, the target server would return the SYN/ACK packet to the host that was spoofed. In which case, wouldn't the spoofed host return an RST packet, thus negating the 75 second long-wait, and ultimately failing in its attempt to DoS the server?

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  • How to debug packet loss ?

    - by Gene Vincent
    I wrote a C++ application (running on Linux) that serves an RTP stream of about 400 kbps. To most destinations this works fine, but some destinations expericence packet loss. The problematic destinations seem to have a slower connection in common, but it should be plenty fast enough for the stream I'm sending. Since these destinations are able to receive similar RTP streams for other applications without packet loss, my application might be at fault. I already verified a few things: - in a tcpdump, I see all RTP packets going out on the sending machine - there is a UDP send buffer in place (I tried sizes between 64KB and 300KB) - the RTP packets mostly stay below 1400 bytes to avoid fragmentation What can a sending application do to minimize the possibility of packet loss and what would be the best way to debug such a situation ?

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  • Protocol/Packet Design Questions

    - by cam
    I'm looking to a design a protocol for a client-server application and need some links to some resources that may help me. The big part is I'm trying to create my own "packet" format so I can minimize the amount of information being sent. I'm looking for some resources to dissect their protocol, but it seems some completely lack packet design, such as SMTP (which just sends strings terminated by CLRF). What are the advantages/disadvantages of using a system like SMTP over a system that uses a custom made packet? Couldn't SMTP use only a couple bytes to cover all commands through bit flags and save bandwidth/space? Just trying to get my head around all this.

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  • Per Application Packet Analyzer

    - by Anindya Chatterjee
    Is there any tool which can analyze network traffic per application? Wireshark does not have per application filtering, fiddler also does not give proper logging for any application. So can anyone please help me out to find an app which can analyze network traffic originating from a random application and log the traffic for that particular application only?

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  • Deciphering Encoding: Packet Analyzation Tools

    - by Zombies
    I am looking for better tools than wireshark for this. The problem with wireshark is that it does not format the data layer (which is the only part I am looking at) cleanly for me to compare the different packets and attempt to understand the third party encoding (which is closed source). Specifically, what are some good tools for viewing data, and not tcp/udp header information? Particularly, a tool that formats the data for comparison. To be very specific: I would like a program that compares multiple (not just 2) files in hex.

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  • Win7 Modifying incoming HTTP packet from specific url automatically

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    Hey, Is there an application that can listen in on my PCs http traffic (Preferably process specific), and modify packets that were requested from a certain url ? So let's say everytime I request http://example.tld/test.html it would replace any occurence of let's say "i" with "I", it's a simple example but still it's an example Thanks for your time, Xeross

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  • Is there a packet sniffer for Windows Mobile?

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  • What is the best way/tool to analyze raw data(network stats) from Simulation?

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  • Sending UDP Packet in C#

    - by DOminik
    Hello everybody! I have a game server (WoW). I want my players to download my custom patches to the game. I've done a program that checks for update/downloading things. I want my program to send a packet to my game server if player have all my patches. I dont need any response from the server, it will handle it, but its another story. So I want to know, how to send a packet to a server. Thank you!

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  • Extracting ID from data packet GPS

    - by user604134
    Hi , I am trying to configure a GPS device to my systems. The GPS device send the data packet to my IP in the following format : $$?W??¬ÿÿÿÿ™U042903.000,A,2839.6408,N,07717.0905,E,0.00,,230111,,,A*7C|1.2|203|0000÷ I am able to extract the latitude, longitude and other information but I am not able to extract the Tracker ID out of the string. According to the manual the ID is in hex format.And the format of the packet is $$\r\n I dont know what to do with it, I have tried converting this to hex..but it didnt work. Any help will be greatly appreciate. Thanks

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