New Exchange 2013 setup - issues with mail flow

[3s-gtech]

Hope someone can help with this, we have a lot of projects rearing their heads at the moment and this is the biggie!

 

We've decided to finally move away from our long-suffering Linux based email solution to Exchange, to try to simplify things like distribution groups, user accounts etc. We've specced the box to (hopefully) support 1000+ users, and it has:

 

4 x quad core opteron

32GB RAM

RAID 1 for OS

RAID 10 for mailstore

RAID 1 for logs.

 

...on bare metal.

 

The machine seems to run fine on Server 2012, and Exchange is installed. I can send mail between a couple of test AD linked accounts on the machine, but I can't seem to send anything out from it to another domain. I have followed the MS guide for adding a send connector (SMTP, * for domain, and setting the Exchange server as the transport). However, if I send an email to my external accounts, nothing gets through. It works from my exiting email account on our old server though, so I don't think they're getting spam-filtered.

 

MX records don't point to the new server as yet, so it can't receive mail for our domain - this shouldn't affect sending though?

 

Not sure what to really look at here, as I have no prior knowledge of Exchange (and only basic knowledge of email systems in general as I didn't build the existing one) - when I check the message queue via Powershell I can see the emails sitting there. There's surely something simple I've missed - everything else has been pretty straightforward so far!

 

Thanks for any assistance with this!

[kmount]

Can the new mail server talk to the outside world on port 25? (to send the mail)

 

Or have you got it configured to relay via a smarthost or something that it can talk to on port 25?

[3s-gtech]

In theory it can talk to the outside world on 25 - unless our LEA have some flow settings of their own going on (our existing email server is on an IP specified by them). No smart hosts or relays I believe, from having played with the current Sendmail config in the past. I could shift the new server over to this IP to test, but obviously this would take the existing system down in the interim.

 

Annoying but predictably, if I try to send to an email address on our current email server to see if that works, I just get a delivery failure because it's not forwarding the email on when no matching address is found (using the same domain name). I could try sending to another school on the WAN to test I guess!

[kmount]

From the exchange server download putty and try and telnet to mail.btopenworld.com on port 25 and see if you get a response.

 

(if you don't, that's your problem!)

[3s-gtech]

I'll give that a shot. My next thought was to set it up to use the existing email server as a relay, which it can do for our subnet. That'll show if the LEA have some settings in place for that IP.

[3s-gtech]

^^It worked! Using the other server as a relay, the email got through to Outlook.com. There must be some settings on the LEA's servers to only route email originating from that IP. In theory, I could leave that server there permanently as a relay, but in practice I'll retire it as soon as I can and shift is across.

 

Next fun job appears to be importing every user from AD (looks like a csv job, which is mad) and migrating emails from old to new (which look horrendous/near impossible - may have to drag and drop using Thunderbird). Any tips on either?

[kmount]

I don't have a mass of experience on the Exchange side (more on the Linux side!) but there are plenty of folks on here who will know the best way to do this.

 

In terms of migrating the mail from the old system you could probably quite easily use imapsync to log into the old server and port the mail across to the new one. (you'll need to make sure IMAP is enabled on the Exch 2013 box - Enable IMAP4 in Exchange 2013: Exchange 2013 Help )

 

For help bulk creating the mailboxes, have a look at - EBUCT–Exchange 2013 Bulk User Creation Tool…