I am testing with our backup mx but it doesn't hold on to mail.
It accepts mail where it's in the mx list
10 mail.soko.nl
20 fallback.soko.nl
it tested sending mail to it and have the firewall closed on the mail.soko.nl for the backup mx so it can't deliver
retry timer is like 5, 10.15, 30, 60, 120, 240, 480, 960, 1440, 1440 so that's for days
still this is in the log
[2019.09.12] 15:40:09.320 [07034] Delivery for richard@soko.nl to richard@sokoisp.nl has bounced. Reason: Remote host said: 601 Attempted to send the message to the following IPs:
[2019.09.12] 15:40:09.320 [07034] DSN email written to 19407051 with status failed to richard@sokoisp.nl
[2019.09.12] 15:40:09.336 [07034] Delivery for richard@soko.nl to richard@sokoisp.nl has completed (Bounced)
[2019.09.12] 16:10:11.355 [63000] Sending remote mail to: richard@sokoisp.nl
[2019.09.12] 16:10:11.355 [63001] Sending remote mail to: richard@sokoisp.nl
[2019.09.12] 16:15:33.043 [63001] Sending remote mail to: richard@sokoisp.nl
[2019.09.12] 16:15:33.043 [63000] Sending remote mail to: richard@sokoisp.nl
[2019.09.12] 16:45:54.124 [63001] Sending remote mail to: richard@sokoisp.nl
[2019.09.12] 16:45:54.124 [63000] Sending remote mail to: richard@sokoisp.nl
[2019.09.12] 16:46:14.125 [63001] Delivery for richard@soko.nl to richard@sokoisp.nl has bounced. Reason: Remote host said: 601 Attempted to send the message to the following IPs:
[2019.09.12] 16:46:14.125 [63000] Delivery for richard@soko.nl to richard@sokoisp.nl has bounced. Reason: Remote host said: 601 Attempted to send the message to the following IPs:
[2019.09.12] 16:46:14.140 [63001] DSN email written to 15492563004 with status failed to richard@sokoisp.nl
[2019.09.12] 16:46:14.140 [63000] DSN email written to 15492563005 with status failed to richard@sokoisp.nl
[2019.09.12] 16:46:14.140 [63001] Delivery for richard@soko.nl to richard@sokoisp.nl has completed (Bounced)
[2019.09.12] 16:46:14.140 [63000] Delivery for richard@soko.nl to richard@sokoisp.nl has completed (Bounced)
When the main mx is open for trafic from the fallback it nicely delivers the mail
but when main mx is unreachable it doesn't take long for the mail is dropped.
what to check?
(both servers v17)