Mailing List Message #105809
From: Tom Rymes <>
Subject: Re: Unique entries for SMTP Prompt Delay
Date: Fri, 11 Sep 2015 08:13:26 -0400
To: CommuniGate Pro Discussions <>
On 09/10/2015 6:06 PM, Juergen P. [core] wrote:

why are you using such a long delay ?

Juergen: This was (and I think still is) a recommended practice to reduce the volume of spam you receive because many spambots would start sending mail before the prompt and CGP will reject mail if you start sending before the prompt is displayed. Perhaps it's not relevant anymore, but I doubt that.

Back in the day (2004), the number of 23s was chosen as the longest that one could use and still have reasonable reliability when sending mail to certain providers. MSN springs to mind for some reason, but I know that used to do a return-path verification that would time out at 30 seconds, so setting your prompt delay to anything beyond 28s was likely to cause problems. The RFC for SMTP, if memory serves, specifies a 5-minute timeout, which is what CGP will respect when sending.

i think, you could use a CGP community-edition as backup-MX for those
mailservers having problems with long delays.

No thank you. I already have enough problems with server-creep around here, and there is a non-zero cost to administering another machine.

If the Delay setting could be changed to be listener-specific, then I could simply modify the firewall to send inbound traffic from specific IP-addresses to listener #2, while listener #1 handled inbound traffic from all non-specified hosts.

CGP: Where can I submit a request for this?


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