Re: TCP stalls in 2.0.33 and 2.1.x

Richard Gooch (rgooch@atnf.CSIRO.AU)
Wed, 18 Mar 1998 23:53:38 +1100

David S. Miller writes:
> Date: Wed, 18 Mar 1998 23:39:43 +1100
> From: Richard Gooch <rgooch@atnf.CSIRO.AU>
>
> OK. I've done as you suggest, with 2.1.90 for machine B. Log
> appended. Machine A is running 2.1.86 and the LAN ftp server is
> running SunOS.
>
> Once again, no data was transferred:
>
> 23:35:31.020079 130.155.194.32.ftp-data > jubemgee.atnf.CSIRO.AU.1027: S 504256000:504256000(0) win 4096 <mss 1460>
>
> SunOS ftp server opens connection with Linux jubemgee (is this Linux
> machine A or B???)

Machine B (2.1.90).

> 23:35:31.020170 jubemgee.atnf.CSIRO.AU.1027 > 130.155.194.32.ftp-data: S 2378695617:2378695617(0) ack 504256001 win 32120 <mss 1460> (DF)
>
> Linux ftp client response.
>
> 23:35:31.150088 130.155.194.32.ftp-data > jubemgee.atnf.CSIRO.AU.1027: . ack 1 win 4096
>
> SunOS ftp server completes the connection.
>
> 23:36:35.500772 jubemgee.atnf.CSIRO.AU.1027 > 130.155.194.32.ftp-data: F 1:1(0) ack 1 win 32120 (DF) [tos 0x8]
> 23:36:38.499838 jubemgee.atnf.CSIRO.AU.1027 > 130.155.194.32.ftp-data: F 1:1(0) ack 1 win 32120 (DF) [tos 0x8]
>
> Linux ftp client closes the connection, this is the only way a FIN
> would be generated. Either your FTP client closed the connection, or
> it core dumped or exited for some other reason.

I did control-C after a minute or so, once I was reasonably sure the
data wasn't coming. The file should have been transferred within a few
seconds or so.

> 23:36:38.611064 130.155.194.32.ftp-data > jubemgee.atnf.CSIRO.AU.1027: . ack 2 win 4096
>
> SunOS FTP server happily acks the FIN.
>
> 23:36:38.611170 jubemgee.atnf.CSIRO.AU.1027 > 130.155.194.32.ftp-data: R 2378695619:2378695619(0) win 0
>
> Linux machine sends a RST back, this is a bug, and I know when I fixed
> this bug, so this Linux machine must be machine A and thus running
> 2.1.86. Therefore you did not do as I suggested.

Nope, the ftp client is running on machine B (2.1.90), which has an
EtherNet connection to machine A (2.1.86), which is the local router
(via SLIP) to a CISCO terminal server, which is on the departmental
LAN. Trust me: I know what keyboard I'm using :-)

Regards,

Richard....

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