On Thu, Jun 02, 2011 at 10:28:18AM -0500, Justin Tocci wrote:
Record complete packets into a file with "tcpdump -s 0 -w", make the
binary packet capture available. Disable TCP window scaling in your
kernel, it may be confusing your router.
The below trace is rather bizarre, something is dreadfully wrong at the
TCP layer.
> mx-ecom.netflix.com.53126 > server.workflowproducts.com.smtp: Flags [S],
> cksum 0x3847 (correct), seq 1705566477, win 5840, options [mss
> 1380,nop,nop,sackOK,nop,wscale 7], length 0
> 09:40:25.853969 IP (tos 0x0, ttl 64, id 65283, offset 0, flags [DF], proto
> TCP (6), length 52, bad cksum 0 (->31cc)!) server.workflowproducts.com.smtp >
> mx-ecom.netflix.com.53126: Flags [S.], cksum 0x0a1b (incorrect -> 0xca96),
> seq 265909580, ack 1705566478, win 65535, options [mss 1460,nop,wscale
> 2,sackOK,eol], length 0
> 09:40:25.945774 IP (tos 0x0, ttl 46, id 45052, offset 0, flags [DF], proto
> TCP (6), length 40) mx-ecom.netflix.com.53126 >
> server.workflowproducts.com.smtp: Flags [.], cksum 0x0a35 (correct), seq 1,
> ack 1, win 46, length 0
> 09:40:25.945796 IP (tos 0x0, ttl 64, id 54885, offset 0, flags [DF], proto
> TCP (6), length 40, bad cksum 0 (->5a76)!) server.workflowproducts.com.smtp >
> mx-ecom.netflix.com.53126: Flags [.], cksum 0x0a0f (incorrect -> 0x0a63), seq
> 1, ack 1, win 65535, length 0
> 09:40:25.948733 IP (tos 0x0, ttl 64, id 30296, offset 0, flags [DF], proto
> TCP (6), length 86, bad cksum 0 (->ba55)!) server.workflowproducts.com.smtp >
> mx-ecom.netflix.com.53126: Flags [.], cksum 0x0a3d (incorrect -> 0x6c2a), seq
> 1:47, ack 1, win 65535, length 46
> 09:40:26.041138 IP (tos 0x0, ttl 46, id 45053, offset 0, flags [DF], proto
> TCP (6), length 40) mx-ecom.netflix.com.53126 >
> server.workflowproducts.com.smtp: Flags [.], cksum 0x0a07 (correct), seq 1,
> ack 47, win 46, length 0
> 09:40:26.041155 IP (tos 0x0, ttl 64, id 8764, offset 0, flags [DF], proto TCP
> (6), length 41, bad cksum 0 (->e9f)!) server.workflowproducts.com.smtp >
> mx-ecom.netflix.com.53126: Flags [P.], cksum 0x0a10 (incorrect -> 0x002c),
> seq 47:48, ack 1, win 65535, length 1
> 09:40:26.129016 IP (tos 0x0, ttl 46, id 45054, offset 0, flags [DF], proto
> TCP (6), length 40) mx-ecom.netflix.com.53126 >
> server.workflowproducts.com.smtp: Flags [.], cksum 0x0a06 (correct), seq 1,
> ack 48, win 46, length 0
> 09:42:26.652346 IP (tos 0x0, ttl 46, id 45055, offset 0, flags [DF], proto
> TCP (6), length 40) mx-ecom.netflix.com.53126 >
> server.workflowproducts.com.smtp: Flags [F.], cksum 0x0a05 (correct), seq 1,
> ack 48, win 46, length 0
> 09:42:26.652366 IP (tos 0x0, ttl 64, id 35596, offset 0, flags [DF], proto
> TCP (6), length 40, bad cksum 0 (->a5cf)!) server.workflowproducts.com.smtp >
> mx-ecom.netflix.com.53126: Flags [.], cksum 0x0a0f (incorrect -> 0x0a33), seq
> 48, ack 2, win 65535, length 0
> 09:42:26.654381 IP (tos 0x0, ttl 64, id 26128, offset 0, flags [DF], proto
> TCP (6), length 40, bad cksum 0 (->cacb)!) server.workflowproducts.com.smtp >
> mx-ecom.netflix.com.53126: Flags [F.], cksum 0x0a0f (incorrect -> 0x0a32),
> seq 48, ack 2, win 65535, length 0
> 09:42:26.741904 IP (tos 0x0, ttl 46, id 0, offset 0, flags [DF], proto TCP
> (6), length 40) mx-ecom.netflix.com.53126 > server.workflowproducts.com.smtp:
> Flags [.], cksum 0x0a04 (correct), seq 2, ack 49, win 46, length 0
--
Viktor.
