Why has SMTP stopped responding or gone slow?
If you TELNET to the SMTP port (25), you find that a connection is established but no SMTP banner will be
presented. It may take several minutes before the usual SMTP banner is displayed.
From 1-Aug-01, MAPS has become a subscription service.
If you are using MAPS for DNSBL, and you have not taken out a subscription with MAPS then your SMTP will appear to stop responding to SMTP connections. In fact, there is a delay of 30 seconds for each DNSBL server check.
GMS Anti-Spam is designed so that if a DNSBL server is down it will ignore the server and continue any other checks as usual. Each check takes 30 seconds before it is aborted and the next check starts.
- Remove the MAPS servers from the DNSBL checks.
- Purchase a plan from MAPS at http://www.mail-abuse.org.
NOTE: This change has affected other MTAs such as PMDF, sendmail, etc.
- Cisco Routers causing SMTP time outs
- Why does my SMTP service suddenly stop?
- GMS and Cisco PIX firewalls
Keywords:DNSBL MAPS SMTP