From: Damrongsak Bulyalert, M.D., Ph.D. (
Date: Tue Jul 23 1996 - 18:28:24 CDT

My original problem was as followed.

> Dear Members:
> I have a SPARC 20 running SUN 5.4 and sendmail 1.31 version.
> The system seemed to be okay until about a week ago, I noticed
> a decrease in traffic of incoming mails. Looking at /var/adm/messages
> file, I found a massive amount of messages like -
> Jul 22 07:56:40 suandok01 sendmail[14069]: AA14069: SYSERR:
> collect: unexpected close, from=<@UBVM.CC.BUFFALO.EDU:
> owner-medlib-l@UBVM.CC.BUFFALO.EDU>:
> Connection reset by peer during collect with

I received prompt responses from:

P. Alejandro Lopez-Valencia <>
Carlos Alexandre Polanczyk <>
Marina Daniels <> provided specific details on how to fix
the problem which was related to /dev/tcp. He suggested the following

/usr/sbin/ndd -set /dev/tcp tcp_ip_abort_interval 480000
/usr/sbin/ndd -set /dev/tcp ip_path_mtu_discovery 0
/usr/sbin/ndd -set /dev/tcp tcp_mss_max 236
/usr/sbin/ndd -set /dev/tcp tcp_rexmit_interval_min 1000
/usr/sbin/ndd -set /dev/tcp tcp_deferred_ack_interval 100
/usr/sbin/ndd -set /dev/tcp tcp_conn_req_max 32

I changed the parameter accordingly and the problem is solved.



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