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Bug #1556
closedMTU setting on NIC interface not considered by af-packet
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Description
When manually changed the MTU if the interface (eth0) to 2800 - just for a test purpose:
root@LTS-64-1:~ # ifconfig docker0 Link encap:Ethernet HWaddr 02:42:33:a5:fe:b7 inet addr:172.17.42.1 Bcast:0.0.0.0 Mask:255.255.0.0 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 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:0 (0.0 B) TX bytes:0 (0.0 B) eth0 Link encap:Ethernet HWaddr 08:00:27:bf:4f:8a inet addr:10.0.2.15 Bcast:10.0.2.255 Mask:255.255.255.0 inet6 addr: fe80::a00:27ff:febf:4f8a/64 Scope:Link UP BROADCAST RUNNING MULTICAST *MTU:2800* Metric:1 RX packets:28636 errors:0 dropped:0 overruns:0 frame:0 TX packets:17366 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:18405349 (18.4 MB) TX bytes:2638374 (2.6 MB) but when Suri is started ...it seems af-packet is still using 1500 as the packet size - aka not taking the MTU into account when no explicit setting is defined in suricata.yaml : 23:01:43 - (flow-manager.c:881) <Info> (FlowRecyclerThreadSpawn) -- using 1 flow recycler threads 23:01:43 - (tm-threads.c:2001) <Notice> (TmThreadWaitOnThreadInit) -- all 2 packet processing threads, 4 management threads initialized, engine started. 23:01:43 - (source-af-packet.c:1365) <Info> (AFPComputeRingParams) -- AF_PACKET RX Ring params: block_size=32768 block_nr=103 frame_size=1584 frame_nr=2060 23:01:43 - (source-af-packet.c:1573) <Info> (AFPCreateSocket) -- Using interface 'eth0' via socket 7 23:01:43 - (source-af-packet.c:1157) <Info> (ReceiveAFPLoop) -- Thread AFPacketeth01 using socket 7 23:01:43 - (source-af-packet.c:1365) <Info> (AFPComputeRingParams) -- AF_PACKET RX Ring params: block_size=32768 block_nr=103 frame_size=1584 frame_nr=2060 23:01:43 - (source-af-packet.c:1573) <Info> (AFPCreateSocket) -- Using interface 'eth0' via socket 8 23:01:43 - (source-af-packet.c:454) <Info> (AFPPeersListReachedInc) -- All AFP capture threads are running.
Updated by Alexander Gozman almost 10 years ago
Maybe it's not a bug but a feature? ;) Is default-packet-size specified in suricata's configuration file? AFAIK suricata checks MTU only if default-packet-size is 0 or unspecified.
Updated by Eric Leblond almost 10 years ago
It works for me (tm) using latest git and when specifying the iface on the command line. But when you have two ifaces you need to setup default-packet-size to the max value or value of first iface will be used. I will submit a PR to improve that.
Updated by Eric Leblond almost 10 years ago
- Status changed from New to Closed
Improvement implemented by https://github.com/inliniac/suricata/pull/1733
Updated by Kristopher Kolpin over 8 years ago
Please see the following issue at:
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