MX Record versus Fixed IP

[kevins74]

I currently have six MX records registered with the ISP for my company.com and the actual names of our mail severs, west.company.com and east.company.com. Right now we use a third party spam filtering company (POSTINI) that has our first four MX records pointing to them. The problem is, spammers are starting at the bottom of our mx records, east.company.com, bypassing the spam filtering.

I'd like to get rid of the east.company.com MX record and move all the remote users outlook configuration from SMTP - east.company.com to just the IP address and then get rid of the MX record. That way the four mx records out there for typical legit mail would go through POSTINI, but the spammers that try to bypass it and go with the bottom MX record would no longer have an MX record to go with.

Is this possible and does this work to just have the IP address used for the smtp server section in the outlook client? I am pretty sure mail would continue without problem for myname@company.com, since that would fall under the first four MX records pointing to POSTINI.

Am I missing something or will this work.

Thanks,

KevinS

 

[ShackDaddy]

Since the MX record is only for mail delivery, why not just remove the MX record and leave the A-record for east.mycompany.com and leave the clients the way they are? That way the spammers don't use that address to send mail anymore, and your client workstations can still point to it as a server to connect to. It's just no longer an internet SMTP endpoint.

ShackDaddy

 

[kevins74]

ShackDaddy,

Thank you,

That is pretty much what I have come up with, but really wanted to hear some others say the same thing making sure I didn't overlook anything. I just wanted to make sure with my testing using the IP for everything, it wasn't still working just because there was that MX record still in place. Since it takes about 24 hours for the mx record to be removed and 24 for it to be returned if there was a problem, I didn't want to be stuck for 48 hours.

But like you said, I am planning on removing the MX record for east.company.com and keeping the A record for east.company.com. Then the outlook configurations can stay east.company.com and I won't have to mess with changing to IP's.

Thanks,

KevinS

 

[Zelandakh]

Kevin,
If postini are doing the spam filtering, set all Exchange servers to only receive email from postini. Then the spammers can't start the bottom.

 

[kevins74]

Zelandakh,

But then out remote users would not be able to send mail via SMTP since our outbound mail doesn't go through Postini, just the inbound.