Date: Wed, 25 Mar 1998 01:11:05 +0000 From: Arman Hazairin <arman@ai3.net> To: bmah@CA.Sandia.GOV Cc: Snob Art Genre <benedict@echonyc.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: TCP connection hang Message-ID: <351859A9.B0D0F9A1@ai3.net> References: <199803241609.IAA08661@stennis.ca.sandia.gov>
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Bruce A. Mah wrote: > > If memory serves me right, Snob Art Genre wrote: > > Your SCO box doesn't seem to be sending a FIN packet to terminate the > > connection. The problem is probably in the application software on the > > SCO side. > > I'm wondering if there isn't something else at work here. Note that at the > end of the trace, the SCO box sent five segments without getting any > acknowledgement back from the FreeBSD machine, yet the FreeBSD machine was > sending back ACK segments mostly normally before. The SCO box never sent any FIN packet because it never finish the transfer. That two boxes just kept silent, SCO waiting for ACK it never received (the last 5 packets in tcpdump output below), the FreeBSD box just kept silent after sending ack for seq. 4225. After all the sequence below, the connection is hang forever until timeout occur. > > Arman Hazairin wrote: > > 15:27:42.040119 20.12.39.21.5577 > 68.10.3.1.1292: . ack 4225 win 16384 > > (DF) > > 15:27:42.207945 68.10.3.1.1292 > 20.12.39.21.5577: . 4225:4737(512) ack > > 1 win 4096 > > 15:27:42.274151 68.10.3.1.1292 > 20.12.39.21.5577: . 4737:5249(512) ack > > 1 win 4096 > > 15:27:42.341464 68.10.3.1.1292 > 20.12.39.21.5577: . 5249:5761(512) ack > > 1 win 4096 > > 15:27:42.408820 68.10.3.1.1292 > 20.12.39.21.5577: . 5761:6273(512) ack > > 1 win 4096 > > 15:27:42.475081 68.10.3.1.1292 > 20.12.39.21.5577: . 6273:6785(512) ack > > 1 win 4096 > > It *almost* looks to me like the FreeBSD host just stopped sending ACKs for > some reason, while the SCO box was several packets (window size 5 segments, > 512-byte MSS) into slow-start. Is it possible that the application on the > FreeBSD box somehow isn't reading the data out of its socket buffers? > > Bruce. If you look into the last ack, it's about 4K of data being transferred. It is almost the same in ftp application, if i do that in that two box, vice versa. I've tried to turn off rfc1323 and rfc1644 option, still doesn't work. Any hint ? -arman- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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