Load Balancing SMTP Traffic

I would like to ask about load balancing SMTP traffic.  We are designing our Exchange 2010 deployment and will be using a netscaler to load balance CAS traffic (OWA, EAS, etc..).  Another question that was asked is whether or not we should be load balancing SMTP traffic?  Currently we have a hosted spam solution that after filtering email sends the message to our HT server.  For 2010 we were thinking of load balancing this and having external email sent to the Netscaler which in turn would handle delivery to the HT servers.  My only concern is since the source IP would be showing as the netscaler and we would need to put the IP pf the VIP in the allowed relay section of the receive connector we in fact would be doing an open relay.. = very bad!

My question is.... is there a way I can do load balancing for SMTP without having this issue?  The only other option would be for our spam service to send directly to the HT servers which then requires those servers to have a public IP which I really dont want to do.  

Thanks.... this is the article I have been reading all day and trying to comprehend

http://exchangeserverpro.com/issues-with-load-balancing-smtp-traffic/
mkllpitAsked:
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.

Simon Butler (Sembee)ConsultantCommented:
Not sure where you have got the idea that you will be an open relay.
I presume you have a list of IP addresses from the external antispam service? If so, configure your firewall to only accept SMTP traffic from them. Send the traffic to the netscaler and configure the receive connector to only accept email from the netscaler. At no point does that turn you in to an open relay (unless you have changed something else in the recieve connector configuration).

Simon.
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
mkllpitAuthor Commented:
Thanks Simon!  I actually thought about that on the way home and it makes perfect sense!
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
Exchange

From novice to tech pro — start learning today.