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SMTP load balancing with cisco

Any one hav experience for load balancing SMTP relay servers (in DMZ) with cisco switches.
Please help

For SMTP relay load balancing which should apply on OS or others, but not switching device.

For exp.

External SMTP load balancing you can use mx record round robin.
Internal SMTP load balancing you can use Ms NLB

anishpeter

ASKER

My device is appliance. I cannot use NLB. As same like we load balance servers and firewalls, can I load balance Mail relays appliances using netwrok load balancing in Cisco?

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gcl_hk

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anishpeter

ASKER

Ok. I agree with you. Then how should I set priority,

SMTP 1 MX 10
SMTP2 MX 20

or

SMTP 1 MX 10
SMTP2 MX 10

Any issues you forsee for old mail realys not adhere to RFC Standard, which is contacting my Mail relay. My one mail relay should work if other server unavilable or SMTP Service hangs.

gcl_hk

Should be same priority for your case.

Check here for more details:
http://www.zytrax.com/books/dns/ch9/rr.html

gcl_hk

This is a good article for you about RR dns
https://www.experts-exchange.com/questions/23656919/DNS-Round-Robin-Query.html

anishpeter

ASKER

But all articles say about load balancing of services. But if one of my SMTP relay fails, what to do?

gcl_hk

Actually I'm not expert on DNS, the following link which have talking about "DNS based Load Balancing with Fault Tolerance", have a look:

http://www.presttun.org/kare/DNS/DNS-LB-FT.pdf

anishpeter

ASKER

Hi.. qcl,
The document is not relevent to SMTP Appliance load balancing. Any more ideas?

anishpeter

ASKER

Any Ideas about SMTP loadbalancing using any hardware appliances. Please reply

anishpeter

ASKER

Good Solution. I have done SMTP loadbalancing and Failover successfully with DNS RR with same priority. Internally I put two Smarthost records.