On 13 February 2013, at 02:29, Eugene Grosbein <egrosb...@rdtc.ru> wrote:
> 13.02.2013 17:25, Doug Hardie пишет: >> Monitoring a tcpdump between two systems, a FreeBSD 9.1 system has the >> following interface: >> >> msk0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 >> >> options=c011b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,TSO4,VLAN_HWTSO,LINKSTATE> >> ether 00:11:2f:2a:c7:03 >> inet 10.0.1.199 netmask 0xffffff00 broadcast 10.0.1.255 >> inet6 fe80::211:2fff:fe2a:c703%msk0 prefixlen 64 scopeid 0x1 >> nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> >> media: Ethernet autoselect (100baseTX >> <full-duplex,flowcontrol,rxpause,txpause>) >> status: active >> >> >> It sent the following packet: (data content abbreviated) >> >> 02:14:42.081617 IP 10.0.1.199.443 > 10.0.1.2.61258: Flags [P.], seq >> 930:4876, ack 846, win 1040, options [nop,nop,TS val 401838072 ecr >> 920110183], length 3946 >> 0x0000: 4500 0f9e ea89 4000 4006 2a08 0a00 01c7 E.....@.@.*..... >> 0x0010: 0a00 0102 01bb ef4a ece1 680b ae37 1bbc .......J..h..7.. >> 0x0020: 8018 0410 3407 0000 0101 080a 17f3 8ff8 ....4...……. >> >> >> The indicated packet length is 3946 and the load of data shown is that size. >> The MTU on both interfaces is 1500. The receiving system received 3 >> packets. There is a router and switch between them. One of them fragmented >> that packet. This is part of a SSL/TLS exchange and one side or the other is >> hanging on this and just dropping the connection. I suspect the packet size >> is the issue. ssldump complains about the packet too and stops monitoring. >> Could this possibly be related to the hardware checksums? > > You have TSO enabled on the interface, so large outgoing TCP packet is pretty > normal. > It will be split by the NIC. Disable TSO with ifconfig if it interferes with > your ssldump. Thanks. Now all the packets are 1500 or under. They all are received with a SSL header. _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
