Date: Tue, 7 Oct 1997 23:22:56 -0200 (EDT) From: Joao Carlos Mendes Luis <jonny@coppe.ufrj.br> To: hackers@freebsd.org Subject: TCP problem Message-ID: <199710080122.XAA00461@gaia.coppe.ufrj.br>
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Hi, I have an intermitent TCP problem between a FreeBSD 2.2-STABLE and a 2.0.27 Linux. It's happening right now, let me show an example: 146.164.5.200 - FreeBSD 146.164.53.91 - Linux gaia::root [530] telnet 146.164.53.91 chargen Trying 146.164.53.91... Connected to gta.ufrj.br. Escape character is '^]'. !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefg !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefgh "#$%&'()*+,-./01^]quit telnet> quit Connection closed. In the above connection, telnet stops completely after some output. Here's the tcpdump output I've run in another window: gaia::root [544] tcpdump -pvn host 146.164.53.91 and port chargen tcpdump: listening on de0 22:49:35.574865 146.164.5.200.2038 > 146.164.53.91.19: S 1153321686:1153321686(0) win 65535 <mss 1460,nop,wscale 1,nop,nop,timestamp[|tcp]> (DF) [tos 0x10] (ttl 64, id 38631) 22:49:35.576498 146.164.53.91.19 > 146.164.5.200.2038: S 2381730138:2381730138(0) ack 1153321687 win 31744 <mss 1460> (ttl 63, id 13086) 22:49:35.576825 146.164.5.200.2038 > 146.164.53.91.19: . ack 1 win 164 (DF) [tos 0x10] (ttl 64, id 38632) 22:49:35.614489 146.164.53.91.19 > 146.164.5.200.2038: P 1:75(74) ack 1 win 31744 (DF) [tos 0x10] (ttl 63, id 13088) 22:49:35.804015 146.164.5.200.2038 > 146.164.53.91.19: . ack 75 win 90 (DF) [tos 0x10] (ttl 64, id 38638) 22:49:36.646712 146.164.53.91.19 > 146.164.5.200.2038: P 75:165(90) ack 1 win 31744 [tos 0x10] (ttl 63, id 13091) 22:49:36.804033 146.164.5.200.2038 > 146.164.53.91.19: . ack 165 win 0 (DF) [tos 0x10] (ttl 64, id 38646) 22:49:38.496284 146.164.53.91.19 > 146.164.5.200.2038: . ack 1 win 31744 [tos 0x10] (ttl 63, id 13096) 22:49:38.496584 146.164.5.200.2038 > 146.164.53.91.19: . ack 165 win 0 (DF) [tos 0x10] (ttl 64, id 38660) 22:49:41.896328 146.164.53.91.19 > 146.164.5.200.2038: . ack 1 win 31744 [tos 0x10] (ttl 63, id 13098) 22:49:41.896640 146.164.5.200.2038 > 146.164.53.91.19: . ack 165 win 0 (DF) [tos 0x10] (ttl 64, id 38673) 22:49:48.696422 146.164.53.91.19 > 146.164.5.200.2038: . ack 1 win 31744 [tos 0x10] (ttl 63, id 13105) 22:49:48.696692 146.164.5.200.2038 > 146.164.53.91.19: . ack 165 win 0 (DF) [tos 0x10] (ttl 64, id 38729) 22:50:02.296514 146.164.53.91.19 > 146.164.5.200.2038: . ack 1 win 31744 [tos 0x10] (ttl 63, id 13163) 22:50:02.296814 146.164.5.200.2038 > 146.164.53.91.19: . ack 165 win 0 (DF) [tos 0x10] (ttl 64, id 38844) ^C 1385 packets received by filter 0 packets dropped by kernel And here, the output on the remote machine: recreio::root [281] tcpdump -pvn host 146.164.5.200 and port chargen tcpdump: listening on eth0 22:47:16.565018 146.164.5.200.2038 > 146.164.53.91.19: S 1153321686:1153321686(0) win 65535 <mss 1460,nop,wscale 1,nop,nop,timestamp 2287877 0,nop,nop,opt-12:00134149> (DF) [tos 0x10] (ttl 63, id 38631) 22:47:16.565018 146.164.53.91.19 > 146.164.5.200.2038: S 2381730138:2381730138(0) ack 1153321687 win 31744 <mss 1460> (ttl 64, id 13086) 22:47:16.565018 146.164.5.200.2038 > 146.164.53.91.19: . ack 1 win 164 (DF) [tos 0x10] (ttl 63, id 38632) 22:47:16.595018 146.164.53.91.19 > 146.164.5.200.2038: P 1:75(74) ack 1 win 31744 (DF) [tos 0x10] (ttl 64, id 13088) 22:47:16.785018 146.164.5.200.2038 > 146.164.53.91.19: . ack 75 win 90 (DF) [tos 0x10] (ttl 63, id 38638) 22:47:17.635018 146.164.53.91.19 > 146.164.5.200.2038: P 75:165(90) ack 1 win 31744 [tos 0x10] (ttl 64, id 13091) 22:47:17.785018 146.164.5.200.2038 > 146.164.53.91.19: . ack 165 win 0 (DF) [tos 0x10] (ttl 63, id 38646) 22:47:19.485018 146.164.53.91.19 > 146.164.5.200.2038: . ack 1 win 31744 [tos 0x10] (ttl 64, id 13096) 22:47:19.485018 146.164.5.200.2038 > 146.164.53.91.19: . ack 165 win 0 (DF) [tos 0x10] (ttl 63, id 38660) 22:47:22.885018 146.164.53.91.19 > 146.164.5.200.2038: . ack 1 win 31744 [tos 0x10] (ttl 64, id 13098) 22:47:22.885018 146.164.5.200.2038 > 146.164.53.91.19: . ack 165 win 0 (DF) [tos 0x10] (ttl 63, id 38673) 22:47:29.685018 146.164.53.91.19 > 146.164.5.200.2038: . ack 1 win 31744 [tos 0x10] (ttl 64, id 13105) 22:47:29.685018 146.164.5.200.2038 > 146.164.53.91.19: . ack 165 win 0 (DF) [tos 0x10] (ttl 63, id 38729) 22:47:43.285018 146.164.53.91.19 > 146.164.5.200.2038: . ack 1 win 31744 [tos 0x10] (ttl 64, id 13163) 22:47:43.285018 146.164.5.200.2038 > 146.164.53.91.19: . ack 165 win 0 (DF) [tos 0x10] (ttl 63, id 38844) 15 packets received by filter 0 packets dropped by kernel As you can see, the connection is in a loop, trying to exchange data, but there's a problem somewhere. The very strange thing is that's intermitent. Most of the time it works perfectly. Also curious, the chargen always stops at the same char. I have no problem connecting from/to other machines to/from both of these. Rebooting the Linux machine does not solve the problem, but rebooting the FreeBSD one does solve, so I think it's a FreeBSD problem. Any suggestions ? This is a RELENG_2_2 distribution, from about one month and half ago. I'm just waiting for a weekend with some free time to upgrade to 2.2.5-beta. Jonny -- Joao Carlos Mendes Luis jonny@gta.ufrj.br +55 21 290-4698 jonny@coppe.ufrj.br Universidade Federal do Rio de Janeiro UFRJ/COPPE/CISI PGP fingerprint: 29 C0 50 B9 B6 3E 58 F2 83 5F E3 26 BF 0F EA 67
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