Skip to main content

Dealing with customers that want their emails to arrive in ~30 seconds

Comments

7 comments

  • cPanelMichael
    Hello @Denis Gomes Franco, It's possible the Introduce a delay into the SMTP transaction for unknown hosts and messages detected as spam option found under the ACL Options tab in WHM >> Exim Configuration Manager >> Basic Editor is having some effect on the delivery speed. The default value is set to delay emails from unknown hosts for 20 seconds. You could explain that part of the reason for the delivery time is to reduce the potential for SPAM. You may also want to perform a test to measure how long it actually takes for delivery from a remote mail server to an email account hosted on the cPanel server. While testing, use the "tail -f /var/log/exim_mainlog" command to monitor which stage of the delivery takes the longest. Thank you.
    0
  • Denis Gomes Franco
    Hi Michael, thanks for getting back to me. There is no ACL tab in Tweak Settings (running v78.0.11 here). I also couldn't find any option with 'DELAY' or 'UNKNOWN' in its nem in Tweak Settings. I actually explained to the customer that 2-3 minutes is quite standard and that Spamassassin actually has to scan messages before delivery, so this should be accounted. I hope this lowered his expectations a little bit. But what about these 'unknown hosts'? Would Cpanel still delay messages from these hosts after receiving one legitimate message from them? Tell me more about it.
    0
  • cPanelMichael
    Hello @Denis Gomes Franco, My mistake, the interface is WHM >> Exim Configuration Manager >> Basic Editor. I've modified my previous post to reflect this.
    But what about these 'unknown hosts'? Would Cpanel still delay messages from these hosts after receiving one legitimate message from them? Tell me more about it.

    Here's the option's description: The SMTP receiver will wait a few additional seconds for a connection when it detects spam messages in order to reduce inbound spam. The system excludes the following remote hosts from the delay: Neighbor IP addresses in the same netblock, Loopback addresses, Trusted Mail Hosts, Relay Hosts, Backup MX Hosts, Skip SMTP Checks Host, Sender Verify Bypass Hosts. The delay is applicable to any remote host that isn't on the exclusion list in the description above. Thank you.
    0
  • Denis Gomes Franco
    Okay, found it and disabled it. I'll ask the customer to test this out. Goddamnit, these people.... Now, as a newbie sysadmin, I'm curious, how does this option help fight spam?
    0
  • cPanelMichael
    Now, as a newbie sysadmin, I'm curious, how does this option help fight spam?

    Legitimate mailing systems will typically wait past the delay, whereas spammers are often unable to wait past the delay because they are trying to send out SPAM to as many email addresses as possible before the spamming server is shutdown or blacklisted. In testing this is shown to be one of the most effective strategies at preventing incoming SPAM messages. Thank you.
    0
  • Denis Gomes Franco
    Isn't that what greylisting is? (Which BTW is disabled in my server). Or is it different? Great explanation, now I have an argument for when the customer starts complaining about too much spam ("You complained about messages getting delayed, so f@ off").
    0
  • cPanelMichael
    Hello @Denis Gomes Franco, Greylisting uses a different method to help prevent SPAM. Here's the description from our
    0

Please sign in to leave a comment.