Hello :-

I work for a small software company which manages its own domain,
which was set up by a previous employee, but I now have a problem I
have not been able to solve.

Our setup had been working without problem since Nov 2001, but
around 1AM Apr 29 2002, we started getting a sharp increase
in logfile messages of the form
  timeout after CONNECT from ...
  lost connection after CONNECT from ...

It only happens from some external mailers; mail from yahoo,
this list, and many others comes through fine.

I've used -v on smtpd, and -D with strace and tcpdump,
but have not been able to pin it down. As near as I can
tell, the remote mailer just does not respond to our
banner, and postfix closes the connection after 300sec.

Things I've tried:
  + telnet to mailx.rtda.com, port 25;
    I see the right banner, and can deposit mail which is
    delivered properly.
  + check fwd and reverse DNS; our ISP is authoritative,
    and initially lacked reverse DNS records, but putting
    them in did not abate the problem.
  + change banner to not say ESMTP;
  + add rule to allow ICMP ping to mailer, instead of dropping it;
    no apparent difference

I'm out of ideas, and any help would be most welcome.

Thanks,
  Alan

Configuration details:
  OS: Linux-Mandrake 8.0 on x86
  Postfix: postfix-20010228-6mdk (from RPM)
  firewall: SonicWall DMZ

Example logfile entries ( tail -2000 /var/log/mail/info | grep '[28346]'
)

May 17 11:59:12 www postfix/smtpd[28346]: >
www.pbspro.com[209.128.88.98]: 220 mailx.rtda.com -- banner
intentionally inscrutable
May 17 11:59:12 www postfix/smtpd[28346]: connect from
www.pbspro.com[209.128.88.98]
May 17 11:59:12 www postfix/smtpd[28346]: watchdog_pat: 0x8074508
May 17 11:59:12 www postfix/smtpd[28346]: vstream_fflush_some: fd 7
flush 56
May 17 12:00:45 www postfix/smtpd[28346]: smtp_get: EOF
May 17 12:00:45 www postfix/smtpd[28346]: lost connection after CONNECT
from www.pbspro.com[209.128.88.98]
May 17 12:00:45 www postfix/smtpd[28346]: disconnect from
www.pbspro.com[209.128.88.98]

Output of postconf -n:

alias_maps = hash:/etc/postfix/aliases
command_directory = /usr/sbin
daemon_directory = /usr/lib/postfix
debug_peer_level = 3
debug_peer_list = pbspro.com
default_privs = nobody
delay_warning_time = 4
mail_owner = postfix
mail_spool_directory = /var/spool/mail
mailbox_command = /usr/bin/procmail -o -a $DOMAIN -d $LOGNAME
masquerade_domains = $mydomain
masquerade_exceptions = root
mydestination = $myhostname, localhost.$mydomain, $mydomain
mydomain = rtda.com
myhostname = mailx.rtda.com
mynetworks = 207.5.83.64/29, 192.168.3.0/24, 192.168.5.0/24, 127.0.0.0/8
myorigin = $mydomain
notify_classes = bounce,delay,policy,protocol,resource,software
queue_directory = /var/spool/postfix
relayhost =
smtpd_banner = $myhostname -- banner intentionally inscrutable
smtpd_client_restrictions = permit_mynetworks
smtpd_sender_restrictions = hash:/etc/postfix/access
transport_maps = hash:/etc/postfix/transport

-- 
Regards, 
  Alan Barclay, RTDA Customer Support             http://www.rtda.com
------------------------------------------------------------------------------
-
To unsubscribe, send mail to majordomopostfix.org with content
(not subject): unsubscribe postfix-users

• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]