When your email server is down....

steve_f

How can you ensure that no incoming emails are lost?

My boss tells me that in our organisation, emails are queued at our ISP if our exchange server is down. The ISP then attempts redelivery every hour. He was cagey about the details of this though. There's a chance he's BSing me, though he did mention something about a second MX record.

I'm very curious about the details of this, thanks!

wastedtime

Not sure about your situation but you could do an nslookup for MX records for the domain in question to see what the domain controller says.

Edit: I should probably say domain name server instead of calling it domain controller.

jibbajabba

Most email server, well all "I" know, do exactly that, re-trying. Normally it retries for example, every 15 minutes, then after the first hour once per hour for a few hours, then once a day etc....

Again, this is just an example, but this is how it normally works. We have reinstalled several email server and even changed the server software itself (i.e Merak > Atmail) and it still delivered them. It all dependson the sending server obviously ... but I don't know any email server which doesn't tr-try ...

In your case he probably had a backup MX setup ..

Open up the command prompt and check it out

Here an example :

Here for example, techexams.net has only one MX record :



Where gmail.com for example, has more backups setup. A lower number is the higher priority MX .. so in this example, if SMTP Server "5" - gmail-smtp-in.l.google.com is down, it re-tries usig "10" - alt1.gmail-smtp-in.l.google.com



So using

set q=mx

in NSLOOKUP - you can check which email server are setup in DNS

steve_f

Thanks everyone for the replies.

The info you have given me has enabled me to do some research, and am now reading about backup MX records and "store and forward" email servers