Q: Why are messages sent to my list being delayed by ten minutes?

By Jacob Haller
Senior Support Engineer, L-Soft

LISTSERV delays messages from non-subscribers and new subscribers for ten minutes by default. It does this as part of its spam prevention system. If a spammer sent identical messages to a large number of email lists and this delay wasn't in place, then early messages in this spam attack might get through. The delay allows time for evidence to accumulate so that LISTSERV can intercept all the messages that are part of the attack.

Understanding the Spam Prevention System in LISTSERV

Whenever LISTSERV receives a message from a non-subscriber, you should see something like this in the LISTSERV log file:

23 Mar 2026 11:50:54 Processing file 0084 from MAILER@LISTS.EXAMPLE.COM
23 Mar 2026 11:50:54 -> Inserting top/bottom banners...
-> Not a subscriber, will process in 10 minutes.

Messages from subscribers who have not posted before have a slightly different log file entry:

23 Mar 2026 12:07:49 Processing file 0089 from MAILER@LISTS.EXAMPLE.COM
23 Mar 2026 12:07:49 -> Inserting top/bottom banners...
-> New subscriber, will process in 10 minutes.

In either case, LISTSERV will reprocess and distribute the message after ten minutes. This default setting is suitable for most situation, but if you have special requirements, the following section outlines some common questions about the spam prevention system and how to customize it.

Frequently Asked Questions About the Spam-Delay Setting

Q1: I don't think this delay is necessary for my email list. Can I change or eliminate it?

A: Yes, you can customize the spam-delay setting by adding Loopcheck= Spam-Delay(x) to the list configuration, replacing "x" with the number of minutes you want the delay to be. A setting of Loopcheck= Spam-Delay(0) will eliminate the delay altogether.

There is also a site-wide setting to change the default spam delay, which can be accessed under "Server Administration > Site Configuration". Simply type SPAM_DELAY in the "Configuration Variable" text box and click on "Search" to find the setting.

When these settings are changed, the new setting will apply to any new messages posted to the email list, but it will not shorten the delay for any messages that are already in the middle of their quarantine. See Question 3 below if that's a concern.

Q2: I sent a message to an email list, and it's currently in the ten-minute delay period, but I don't want it to go out. What can I do?

A: There are several ways you can approach this.

Option 1: If you go into the listserv\spool\ (under Windows) or the ~listserv/spool/ (under Unix) directory and find the .jobh file that corresponds to the message in question, you can delete the .jobh file to prevent the message from being reprocessed. The jobh file would have been created at the time LISTSERV originally processed the message, and its name will include the name of the email list.

If you want to see what's in the file before deleting it to make sure it's the correct one, then you can use the "jobview" executable that should be in the same directory to view its contents.
Option 2: You can change the "Send" list configuration setting so that the person who posted the message is no longer allowed to post to the list. This should prevent distribution once the ten-minute quarantine period is over. You can then change the setting back to whatever it was originally, if desired.

Q3: A message has been sent and is in the middle of the ten-minute quarantine, but I would like it to go out as soon as possible. What can I do?

A: If you update the list configuration with Loopcheck= Spam-Delay(0) and restart LISTSERV, then LISTSERV should immediately reprocess and distribute the message. Once you've confirmed that it has gone out, you can change the configuration back to what it was originally, if desired.

This is only necessary if a message was sent already, has been held due to the default spam delay, has not yet been reprocessed, and you cannot wait another few minutes for it to be distributed. The purpose of the restart is to force LISTSERV to rescan the spool for held jobs and check whether they should still be in quarantine.

If the message hasn't been sent yet and if it's fine for this particular message to be delayed another few minutes as long as future messages aren't delayed, then restarting LISTSERV is not necessary as the updated setting will take effect immediately for all new messages sent to the list.

Q4: Mail is being delayed, but I don't see the "Not a subscriber" or "New subscriber" log file entries described above. What could be going on?

A: Although the situation described in this tech tip is the most common reason for ten-minute delays in messages being distributed to email lists, delays can also occur for a variety of other reasons. In general, the first step is to find out exactly where on the message's journey the delay was introduced and then focus your investigation on that point.

The email headers can be very useful in this regard, and the MXToolbox website has some information about how to access a message's headers at:
https://mxtoolbox.com/Public/Content/EmailHeaders/

Some tools to help analyze them are available at:
https://mxtoolbox.com/EmailHeaders.aspx

(Note that MXToolbox is unaffiliated with L-Soft.)

If you forward the email message headers to L-Soft Support, then we are also happy to help analyze them.