As per an earlier post to this ML about slow email sending, the problem was narrowed down to callout verifications on recipients: exim was slowly verifying one recipient after another, locking down the user's email program for literally hours for legit emails.
This doesn't seem to make any sense and after more testing, it seems that exim is not caching any previous callout verification results. When sending to a recipient the first time, it takes about 20 seconds to complete the verification, sending a second email still takes the same amount of time to do verification. In debug mode, exim says there is no domain/address found in cache despite sending to the same recipient twice in a row. 3714 opened hints database /var/spool/exim/db/callout: flags=O_RDWR 3714 dbfn_read: key=gmail.com 3714 callout cache: no domain record found for gmail.com 3714 dbfn_read: [email protected]/<[email protected]> 3714 callout cache: no address record found for [email protected]/<[email protected]> I've deleted the /var/spool/exim/db/callout file in case it was corrupted and saw that it was recreated and updated as emails are sent. Yet exim does not appear to be able to find any matches in it. What could be the problem here? -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
