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[lvs-users] LVS-DR: director cuts packets with payload size > MSS (1460)
hello,
i have strange issue with LVS in direct routing mode - Director forwards
between interfaces packets with payload < 1460 only
see below dumps from two interfaces on same box where eth1 is incoming
interface where VIP is up, and eth0 is outgoing interface to real-servers.
A packet with id 11270 (length 2960) is present in incoming traffic but
absent in outgoing. Same with packet id 11279
why this may happens ?
I am running kernel 3.8.13 without conntrack.
look what happens on interfaces as tcpdump shows:
eth1 is incoming interface where VIP 10.1.1.60 is up:

(virtual) foto1 ~ # tcpdump -i eth1 -vv -n port 80 and host 10.1.1.145


tcpdump: listening on eth1, link-type EN10MB (Ethernet), capture size 68
bytes

16:38:34.896032 IP (tos 0x0, ttl 128, id 11268, offset 0, flags [DF], proto
TCP (6), length 52) 10.1.1.145.63094 > 10.1.1.60.80: S
1211165489:1211165489(0) win 8192 <mss 1460,[|tcp]>

16:38:34.896843 IP (tos 0x0, ttl 128, id 11269, offset 0, flags [DF], proto
TCP (6), length 40) 10.1.1.145.63094 > 10.1.1.60.80: ., cksum 0x6192
(correct), 1211165490:1211165490(0) ack 2881536955 win 64240

16:38:34.896978 IP (tos 0x0, ttl 128, id 11270, offset 0, flags [DF], proto
TCP (6), length 2960) 10.1.1.145.63094 > 10.1.1.60.80: . 0:2920(2920) ack 1
win 64240

16:38:35.206653 IP (tos 0x0, ttl 128, id 11273, offset 0, flags [DF], proto
TCP (6), length 1500) 10.1.1.145.63094 > 10.1.1.60.80: . 0:1460(1460) ack 1
win 64240

16:38:35.207487 IP (tos 0x0, ttl 128, id 11274, offset 0, flags [DF], proto
TCP (6), length 1500) 10.1.1.145.63094 > 10.1.1.60.80: . 2920:4380(1460) ack
1 win 64240

16:38:35.207538 IP (tos 0x0, ttl 128, id 11275, offset 0, flags [DF], proto
TCP (6), length 1500) 10.1.1.145.63094 > 10.1.1.60.80: . 4380:5840(1460) ack
1 win 64240

16:38:35.208593 IP (tos 0x0, ttl 128, id 11276, offset 0, flags [DF], proto
TCP (6), length 1500) 10.1.1.145.63094 > 10.1.1.60.80: . 1460:2920(1460) ack
1 win 64240

16:38:35.209105 IP (tos 0x0, ttl 128, id 11277, offset 0, flags [DF], proto
TCP (6), length 2960) 10.1.1.145.63094 > 10.1.1.60.80: . 5840:8760(2920) ack
1 win 64240

16:38:35.209145 IP (tos 0x0, ttl 128, id 11279, offset 0, flags [DF], proto
TCP (6), length 2960) 10.1.1.145.63094 > 10.1.1.60.80: . 8760:11680(2920)
ack 1 win 64240
eth0 is outgoing to real-servers interface on same server:
(virtual) foto1 ~ # tcpdump -i eth0 -vv -n port 80 and host 10.1.1.145
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 68
bytes
16:38:34.896070 IP (tos 0x0, ttl 128, id 11268, offset 0, flags [DF], proto
TCP (6), length 52) 10.1.1.145.63094 > 10.1.1.60.80: S
1211165489:1211165489(0) win 8192 <mss 1460,[|tcp]>
16:38:34.896863 IP (tos 0x0, ttl 128, id 11269, offset 0, flags [DF], proto
TCP (6), length 40) 10.1.1.145.63094 > 10.1.1.60.80: ., cksum 0x6192
(correct), 1211165490:1211165490(0) ack 2881536955 win 64240
16:38:35.206692 IP (tos 0x0, ttl 128, id 11273, offset 0, flags [DF], proto
TCP (6), length 1500) 10.1.1.145.63094 > 10.1.1.60.80: . 0:1460(1460) ack 1
win 64240
16:38:35.207505 IP (tos 0x0, ttl 128, id 11274, offset 0, flags [DF], proto
TCP (6), length 1500) 10.1.1.145.63094 > 10.1.1.60.80: . 2920:4380(1460) ack
1 win 64240
16:38:35.207542 IP (tos 0x0, ttl 128, id 11275, offset 0, flags [DF], proto
TCP (6), length 1500) 10.1.1.145.63094 > 10.1.1.60.80: . 4380:5840(1460) ack
1 win 64240
16:38:35.208610 IP (tos 0x0, ttl 128, id 11276, offset 0, flags [DF], proto
TCP (6), length 1500) 10.1.1.145.63094 > 10.1.1.60.80: . 1460:2920(1460) ack
1 win 64240
16:38:35.520432 IP (tos 0x0, ttl 128, id 11282, offset 0, flags [DF], proto
TCP (6), length 1500) 10.1.1.145.63094 > 10.1.1.60.80: . 5840:7300(1460) ack
1 win 64240
16:38:35.523322 IP (tos 0x0, ttl 128, id 11283, offset 0, flags [DF], proto
TCP (6), length 1500) 10.1.1.145.63094 > 10.1.1.60.80: . 11680:13140(1460)
ack 1 win 64240

Thanks in advance,
Deniss
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