Deny MX queries for dynamic IP pools

[Matus UHLAR - fantomas]

>> At 05:25 31-01-10, Wael Shaheen wrote:
>>> As a solution the routing team was thinking to block port 25 for
>>> outgoing as some ISPs do. However, I do not see this to be a valid
>>> solution for many reasons such as clients that have email servers
>>> outside, or if decided to be redirected to spam filters then that will
>>> just cost the company too much.

> On 1/31/2010 4:18 PM, SM wrote:
>> Mail submission is done over port 587 and not port 25.

On 01.02.10 13:29, Kevin Darcy wrote:
> MTA-to-MTA traffic uses port 25.

> Also, older MUAs will still often use port 25 even for message  
> submission, and so will spammers, if they think it will help them bypass  
> anti-spam protections built into the MSA.

those are exactly the reasons why some ISPs block port 25 access.
however this is really off-topic here. and I think DNS is really bad place
to solve this problem, as it is for failover switching and helping http
clients to find out correct site in case of mistake.

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Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
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