I setup (as you know) the multi server debian 10, 7 machines. Followed your tutorial and its all working but using ISPConfig 3.2dev20210820, as i encountered the bug for self generated cert failure. When will you merge working code to stable so i can then upgrade all the servers? Issue i have found as well, the tutorial states a backup mail server (mx2), but when testing the webmail server.. i unplugged network lead to simulate broken mail server and sent emails to test email address, the webmail server doesnt show that email. So, do i just add another a dns record stating mail - IP of backup server ? what is the best method to achieve is a server goes offline secondary mail server takes up the slack until primary is up again without human intervention? Cheers and keep up the good and excellent work
As described in the guide, you should create some necessary DNS records. In this case, you would need a A record for mx1.example.com pointing to the main nameserver and mx2.example.com pointing to the secondary server. For all domains that should have their e-mail delivered to your servers, add 2 MX records, both with the same priority, one pointing to mx1.example.com., and one pointing to mx2.example.com.
The MX record is incorrect, it should point to mx1 and you should add a second record pointing to mx2.
Thanks Th0m, testing now.. Also noted that webmail server doesnt replicate to second server based on tutorial, what do you suggest to change to make webmail server use mx1 & mx2 to send/recive emails with backup replication in mind. or isnt this possible in this setup. tried sending and webmail wont, it also wont receive any emails when mx1 unplugged from switch, if plugged in it will send/receive.
Yes, that's intended. Only receiving will work, so it "instantly" works when the other server is back up. For real redundancy, you need to set up a high available proxy in front of it.
have sent email to test email, its not receiving it. Tested and failed the DNS - now displays mx1.tlwebservices.co.uk.tlwebservices.co.uk with mxtoolbox.com - https://mxtoolbox.com/SuperTool.aspx?action=mx:tlwebservices.co.uk&run=toolpage this is mostly my dns entries
You are missing the periods at the end of the hostnames in your mx records. (alternately, you can just enter 'mx1' and 'mx2')
