Date: Wed, 17 Jul 2002 00:00:18 -0500 (CDT) From: Mike Silbersack <silby@silby.com> To: Alex Dyas <alexdyas@hotmail.com> Cc: net@freebsd.org Subject: Re: BSD / Firewall / 0 window size problem Message-ID: <20020716235818.K79793-100000@patrocles.silby.com> In-Reply-To: <F175KzGZuNY1SWoBDys00012182@hotmail.com>
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On Tue, 16 Jul 2002, Alex Dyas wrote: > I've attached a tcpdump of a Linux machine doing the same thing > (working.txt). > > the same 0 sized window can be seen: > > 17:15:56.094161 linuxbox.foo.com.3479 > solarisbox.foo.com.telnet: . ack 456 > win 5840 <nop,nop,timestamp 176027347 193370834> (DF) [tos 0x10] > 17:16:12.634540 solarisbox.foo.com.telnet > linuxbox.foo.com.3479: . ack 74 > win 0 > 17:16:12.634540 linuxbox.foo.com.3479 > solarisbox.foo.com.telnet: . ack 456 > win 5840 <nop,nop,timestamp 176029001 193370834> (DF) [tos 0x10] > > but the Linux telnet session does not freeze up as the BSD one does. > > Again, any help would be most appreciated. > > Thanks again, > > Alex... As Barney noted, the behavior of both OSes looks very similar. Have you run tcpdump on the solaris box at the same time? That win 0 packet looks _really_ suspicious to me; it doesn't share the DF bit or timestamps of the other packets in the stream. On top of that, I see no reason why a win 0 should be sent when the previous window was ~24K in size. Is it possible that the NAT box is adding it in? Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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