Date: Tue, 28 Jan 1997 13:59:55 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: brian@burton-computer.com (Brian Burton) Cc: shovey@buffnet.net, terry@lambert.org, robert@nanguo.chalmers.com.au, freebsd-questions@freebsd.org, freebsd-isp@freebsd.org Subject: Re: progress report on connection problems Message-ID: <199701282059.NAA08968@phaeton.artisoft.com> In-Reply-To: <32EE624B.773C2448@burton-computer.com> from "Brian Burton" at Jan 28, 97 03:32:11 pm
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> If anyone has any ideas or suggestions I'd be happy to hear them.
[ ... ]
> Here is an excerpt from the tcpdump of my side of a hung ftp to caldera.
[ ... ]
> 15:25:16.874058 caldera.com.ftp-data >
> bcc01.burton-computer.com.40001: S 4117168473:4117168473(0) win 512 <mss
> 1460> [tos 0x8]
> 15:25:16.874257 bcc01.burton-computer.com.40001 >
> caldera.com.ftp-data: S 3890833409:3890833409(0) ack 4117168474 win
> 17520 <mss 1460> (DF)
> 15:25:17.025729 caldera.com.ftp-data >
> bcc01.burton-computer.com.40001: . ack 1 win 31744 [tos 0x8]
*****
Caldera acks us...
> 15:25:19.873299 caldera.com.ftp-data >
> bcc01.burton-computer.com.40001: P 1:1025(1024) ack 1 win 31744 (DF)
> [tos 0x8]
Caldera sends us data...
> 15:25:19.921828 bcc01.burton-computer.com.40001 >
> caldera.com.ftp-data: . ack 1025 win 17520 (DF) [tos 0x8]
We ack Caldera (successfully for 1..1024, next send from offset 1025)...
> 15:25:19.969787 caldera.com.ftp-data >
> bcc01.burton-computer.com.40001: P 1025:2485(1460) ack 1 win 31744 (DF)
> [tos 0x8]
Caldera sends us more data...
> 15:25:20.121842 bcc01.burton-computer.com.40001 >
> caldera.com.ftp-data: . ack 2485 win 17520 (DF) [tos 0x8]
We ack Caldera (successfully for 1024..2484, next send from offset 2485)...
> 15:25:20.313058 caldera.com.ftp-data >
> bcc01.burton-computer.com.40001: P 3945:4450(505) ack 1 win 31744 (DF)
> [tos 0x8]
Caldera skips 2485..3944 (THEY ARE BROKEN!)...
> 15:25:20.313167 bcc01.burton-computer.com.40001 >
> caldera.com.ftp-data: . ack 2485 win 17520 (DF) [tos 0x8]
We ack Caldera (successfully for 1024..2484, next send from offset 2485)
to get it to back up to that offset and resend...
> 15:25:20.497450 caldera.com.ftp-data >
> bcc01.burton-computer.com.40001: F 4450:4450(0) ack 1 win 31744 [tos
> 0x8]
Caldera loses its mind and sends us totally bogus crap...
> 15:25:20.497542 bcc01.burton-computer.com.40001 >
> caldera.com.ftp-data: . ack 2485 win 17520 (DF) [tos 0x8]
We ack Caldera (successfully for 1024..2484, next send from offset 2485)
to get it to back up to that offset and resend...
<where is Caldera???>
> 15:26:33.252421 bcc01.burton-computer.com.40001 >
> caldera.com.ftp-data: F 1:1(0) ack 2485 win 17520 (DF) [tos 0x8]
We ack Caldera (successfully for 1024..2484, next send from offset 2485)
to get it to back up to that offset and resend...
> 15:26:33.443142 caldera.com.ftp-data >
> bcc01.burton-computer.com.40001: . ack 2 win 31744 [tos 0x8]
Caldera ack 2's us back for no good reason...
***
***
***
*** It is apparrent that someone in the link can not handle
*** piggyback ack data.
***
***
***
> Here is an excerpt from my ISP's side of the failed ftp.
>
> 20:27:16.862191 caldera.com.20 > bcc01.burton-computer.com.40001: S
> 4117168473:4117168473(0) win 512 <mss 1460> [tos 0x8]
Negotiate...
> 20:27:16.889774 bcc01.burton-computer.com.40001 > caldera.com.20: S
> 3890833409:3890833409(0) ack 4117168474 win 17520 <mss 1460> (DF)
Negotiate back at them...
> 20:27:17.014076 caldera.com.20 > bcc01.burton-computer.com.40001: .
> ack 1 win 31744 [tos 0x8]
They ack ISP...
> 20:27:19.793237 caldera.com.20 > bcc01.burton-computer.com.40001: P
> 1:1025(1024) ack 1 win 31744 (DF) [tos 0x8]
They send ISP 1..1024
> 20:27:19.825641 caldera.com.20 > bcc01.burton-computer.com.40001: P
> 1025:2485(1460) ack 1 win 31744 (DF) [tos 0x8]
They send ISP 1025..2484
> 20:27:19.937915 bcc01.burton-computer.com.40001 > caldera.com.20: .
> ack 1025 win 17520 (DF) [tos 0x8]
ISP acks for 1..1024, next send from offset 1025...
<MORE MISSING DUMP DATA?>
> 20:27:20.140595 bcc01.burton-computer.com.40001 > caldera.com.20: .
> ack 2485 win 17520 (DF) [tos 0x8]
ISP acks for 1024..2484, next send from offset 2485...
> 20:27:20.170151 caldera.com.20 > bcc01.burton-computer.com.40001: P
> 2485:3945(1460) ack 1 win 31744 [tos 0x8]
Caldera sends 2485..3944 (why didn't the ISP send it to us?!?)
> 20:27:20.173851 caldera.com.20 > bcc01.burton-computer.com.40001: P
> 3945:4450(505) ack 1 win 31744 (DF) [tos 0x8]
Caldera sends 3945..4449 (but they send it without an ack...)
> 20:27:20.329662 bcc01.burton-computer.com.40001 > caldera.com.20: .
> ack 2485 win 17520 (DF) [tos 0x8]
ISP acks for 1024..2484, next send from offset 2485...
> 20:27:20.477486 caldera.com.20 > bcc01.burton-computer.com.40001: F
> 4450:4450(0) ack 1 win 31744 [tos 0x8]
Caldera loses its mind and sends us totally bogus crap...
> 20:27:20.516980 bcc01.burton-computer.com.40001 > caldera.com.20: .
> ack 2485 win 17520 (DF) [tos 0x8]
ISP acks for 1024..2484, next send from offset 2485...
> 20:27:21.956979 caldera.com.20 > bcc01.burton-computer.com.40001: P
> 2485:3945(1460) ack 1 win 31744 [tos 0x8]
Caldera resends 2485..3945
> 20:27:25.612874 caldera.com.20 > bcc01.burton-computer.com.40001: P
> 2485:3945(1460) ack 1 win 31744 [tos 0x8]
Caldera sends 3945..4449 (but they send it without an ack...)
> 20:27:32.965838 caldera.com.20 > bcc01.burton-computer.com.40001: P
> 2485:3945(1460) ack 1 win 31744 [tos 0x8]
Caldera resends 2485..3945 without being asked to do so...
> 20:27:47.853712 caldera.com.20 > bcc01.burton-computer.com.40001: P
> 2485:3945(1460) ack 1 win 31744 [tos 0x8]
Caldera resends 2485..3945 without being asked to do so...
> 20:28:16.896253 caldera.com.20 > bcc01.burton-computer.com.40001: P
> 2485:3945(1460) ack 1 win 31744 [tos 0x8]
Caldera resends 2485..3945 without being asked to do so...
> 20:28:33.290671 bcc01.burton-computer.com.40001 > caldera.com.20: F
> 1:1(0) ack 2485 win 17520 (DF) [tos 0x8]
ISP loses its mind and sends bogus crap...
> 20:28:33.451976 caldera.com.20 > bcc01.burton-computer.com.40001: .
> ack 2 win 31744 [tos 0x8]
Caldera ack 2's ISP back for no good reason...
***
***
***
***
*** The piggyback failure is at the ISP...
***
***
***
***
Regards,
Terry Lambert
terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.
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