Reverse Dns Question...is it really necessary or not?

[Chip Mefford]

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Barry Margolin wrote:
| In article <cdjig9$1p1r$1 at sf1.isc.org>, Chip Mefford <cpm at well.com>
| wrote:
|>Simon Hobson wrote:
|>| Chip Mefford wrote:
|>|
|>|>They may indeed have address->name mappings, but very seldom does
|>|>one have an MX record. Not MX record, then it is not a legitimate
|>|>mail relay.
|>| Can I clarify what you mean here ?
|>
|>Sure.
|>| I read it as, if the mx record doesn't match the sending IP address,
|>| then the sending machine is not legitimate. That makes all our
|>| outgoing mail illegitimate then !
|>
|>No, however a lot of folks (and I have *NOT* done this) use the MX
|>mapping thing as a rule in their spam fighting attempts.
|>This would be folks like compuserve in europe, apple.com aol.com and
|>some others.
|
| I find this difficult to believe,

Okay.

| I'm virtually certain that AOL uses
| different servers for incoming and outgoing mail,

They do.

| so it's totally
| impractical for other large ISPs to perform such checks.

Be that as it may, there was a problem, making the MX=A=PTR=HOST
fixed the problem. There was no longer a problem. The question
was asked, I answered it to the best of my ability, the answer
worked, and it has for more a number of folks running small networks
in the /30 to /25 range.

- --chipper
(who isn't sure how he got to be the bad guy).

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