https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=30013 Bug ID: 30013 Summary: Limit/throttle SMTP connections Change sponsored?: --- Product: Koha Version: master Hardware: All OS: All Status: NEW Severity: enhancement Priority: P5 - low Component: Notices Assignee: koha-bugs@lists.koha-community.org Reporter: magnus@libriotech.no QA Contact: testopia@bugs.koha-community.org We have a setup where Koha is sending email through the SMTP server of the library's mother institution. We are seeing a problem with sending lots of emails in one go, where the first emails are sent ok, but then the rest fail with an error like this: unable to establish SMTP connection to (mail.x.y) port 25 It looks like this is due to some limit on the server, making it unresponsive if there are too many connections from the same source in a short time. I don't know a lot about SMTP but I can imagine a couple of solutions: - Introduce a configurable "sleep" period between each call to the external SMTP server (or batches of a configurable number, with a configurable sleep between each batch) - Looking at the response from the server and if "unable to establish SMTP connection" is received, wait for a configurable amount of time before trying to resend the failed message and the rest of the queue -- You are receiving this mail because: You are watching all bug changes. You are the assignee for the bug.