Redundant mail path for Exchange 2003

Hi, we have 2 x offices connected via WAN. Each office has its own internet connection (separate to our WAN connection), but all email comes into office 1. The exchange server here then passes emails to the server in office 2.


The internet in office 1 was down all of yesterday, which made me think, is there a way we can redirect our email (ingoing / outgoing) through our office 2 server?

My understanding of it is we can add another SMTP connector to both servers with a higher cost, so exchange will fall back to the secondary connection if it needs to.

We only have 1 server per site, so I'm not sure about this front end / back end / bridgehead arrangement. But I am also curious to know if mail starts coming in through exchange server 2, will it know to automatically send mail up to exchange server 1? (as it has never had to do this before, usually its the other way around)


My thinking may be way out here, hope someone can help out!
LVL 11
dekkarAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

dnilsonCommented:
Configure a MTA connection between the two servers, setup the DNS to use both SMTP servers using mx records and wail away!
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Dave HoweSoftware and Hardware EngineerCommented:
if they are both part of the same email domain, then yes, it will pass the message correctly to whichever server has the mailstore for that user.

and yes, adding a second bridgehead (with higher cost) to the second office will allow fallback to that if the primary bridgehead is unavailable - it may not fail back automatically though, as in exchange's opinion, the bridgehead is "up" - its all the rest of the internet that is down :(

getting inbound routing is simple - just add a second MX record to your dns (with a higher value than the primary) pointing at the internet NAT address for the second bridgehead.
0
MesthaCommented:
Sorry to say, but adding another SMTP connector with a higher cost will NOT give you redundancy.
If the primary connection is not available, Exchange will not try the higher cost connector. It will simply queue the email.

Exchange matches the address space, if there are two connectors with * but different costs then the lowest cost will always be used and the higher cost ignored. Costs are designed for use with specific domains, so you would have example.com with a cost of 1 and * with a cost of 2, then email for example.com would go out the first connector and then everything else out the second connector.

The most that you can do is load balancing, with two connectors of a cost of 1, or two bridgeheads set in the same connector.

With regards to inbound email, as far as I am concerned, all MX records are equal. Furthermore if you do set a second connector with a higher value, then it will receive more spam than the lower cost. Therefore if you are going to have both servers exposed to the internet then you need to ensure that both servers have the same Antispam and Antivirus solution installed. They need to be configured identically, so recipient filtering etc enabled.

Simon.
0
Problems using Powershell and Active Directory?

Managing Active Directory does not always have to be complicated.  If you are spending more time trying instead of doing, then it's time to look at something else. For nearly 20 years, AD admins around the world have used one tool for day-to-day AD management: Hyena. Discover why

Dave HoweSoftware and Hardware EngineerCommented:
Mestha: yep, my point exactly. however, you can run a scheduled job to ping a remote IP, and shut down or start up the service as appropriate.
0
MesthaCommented:
Start what service?
There is no way to control the routing in Exchange depending on whether something is down or not. You cannot stop SMTP because that will affect inter-server traffic as well.

If there are multiple sites then another way round it is to use a smart host that is under your control. That is what I do with a number of clients. Doesn't matter where the email originates from, it all leaves via a single host on the internet (actually a cluster of machines, but it is a single "host" name).

Simon.
0
Dave HoweSoftware and Hardware EngineerCommented:
Mestha: on the script I use, it uses Set-SendConnector with the -enabled parameter to shut down the bridgehead unless it can successfully ping the upstream router at the ISP.
0
MesthaCommented:
This is a question about Exchange 2003. So Powershell doesn't apply.

Simon.
0
Dave HoweSoftware and Hardware EngineerCommented:
hmm. I didn't think exchange 2003 used smtp for links between servers, I thought it used rpc?
0
MesthaCommented:
Inter-server traffic goes over SMTP. That has been the case since Exchange 2000. That is why you will see in all the migration questions the first thing that is asked is about SMTP connectivity.
Stop SMTP and no traffic will flow between them. Try it and see.

Simon.
0
dekkarAuthor Commented:
Hi... Thanks for the replies... It does shed some light on inbound, which is pretty straight forward. Outbound however seems to be impossible to have redundancy?

Does Exch 2007 provide this? As it could be the excuse I'm looking for to upgrade!


Thanks,
Dekkar
0
MesthaCommented:
The behaviour hasn't changed. All it does is load balance, nothing else.

Simon.
0
dekkarAuthor Commented:
working.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Email Protocols

From novice to tech pro — start learning today.