smtp load balancer???

Denis Beauchemin Denis.Beauchemin at USHERBROOKE.CA
Wed Dec 7 20:37:38 GMT 2005

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Chris Conn wrote:

> Joshua Hirsh wrote:
>>> I am considering adding an SMTP load balancer in front of my MS 
>>> servers.
>>> Any suggestions?
>> Hi Denis,
>>  Have you tried setting up multiple A records for one MX, instead of 
>> two equal value records?
>> For example:
>>    IN    MX    5
>> smtpe1        IN    A
>> smtpe1        IN    A
>>  It might be cheaper instead of buying a device to actually balance 
>> it out, but I don't have any data on how well this balances out the 
>> requests as compared to how you have it setup now (two equal value MX 
>> records).
> If you go the DNS route, reduce your TTL to a small value (ie 5 or zero).
> If you are using Cisco, SLB is a simple and effective way to go.  
> Provides health-checking too.


I've been told (and have verified it on many occasions) that big ISPs 
don't care about the TTL we define for our DNS entries.  They will 
override our TTL with their default value which could be as high as many 


  °v°   Denis Beauchemin, analyste
 /(_)\  Université de Sherbrooke, S.T.I.
  ^ ^   T: 819.821.8000x2252 F: 819.821.8045

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