Round-Robin for mail/smtp hosts

[Brad Knowles]

At 6:43 PM -0700 7/3/01, Matt Prigge wrote:

>      I have seen many discussions on this list about using multiple A records
>  for load balancing and redundancy in HTTP/WWW applications. However, I
>  wanted to know if there are any problems with using them for other
>  applications such as balancing between two outgoing mail servers or between
>  two pop/imap servers. I personally cant think of any (which is why Im
>  asking). Please note that I am not talking about using multiple A records
>  for MX hosts, just about the address that a client might punch into Outlook
>  Express or Netscape to check and send their mail.

	No, it's not generally a problem.  However, note that all 
Microsoft clients I know of will only ever contact the first IP 
address they are told about, regardless of how many IP addresses you 
may list.  This is why you need a proper L4 load-balancing switch, so 
that you can put multiple machines behind a single published IP 
address.

-- 
Brad Knowles, <brad.knowles at skynet.be>

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