New Zone?

[lbarron]

Hi,

We have an email server which is accessible from the outside via mail.domain.com

As our internal domain doesn't match our external when users are on the LAN they have to use the server name or IP to access the web mail.

If we wanted them to be able to use mail.domain.com internally would we just have to create a new zone within DNS for domain.com and then add an A record pointing to the internal IP?

Any help would be appreciated

Thanks

Lee

 

[VinceWhirlwind]

They resolve mail.domain.com the same way they resolve any other name: the local DNS server is queried, and that server looks it up on the internet if it has no local record.
So, if you want your internal hosts to not look it up on the internet, make a local record.

 

[lbarron]

Thanks for your reply.

As the domain.com doesn't match our local domain do we need to create a new forward lookup done or just add an A record?

Lee

 

[HopnDude]

Wouldn't that be setup by a two way trust between domains?

 

[ShackDaddy]

The best way is to create a new internal forward look up zone FOR THE EXACT NAME YOU WANT TO RESOLVE, and then create an "@" record in that zone that points to the internal IP.

So you'd create a forward lookup zone for "mail.domain.com" and not just "domain.com".

Why? If you create a zone for "domain.com" and then create an A-record for "mail", your client's won't be able to resolve "ftp.domain.com" or "

http://www.domain.com"

without you creating specific records for those, and those might change over time, so you are creating a brittle construction.

If you just create a zone for "mail.domain.com" and create a "blank" or "@" record that maps to your server's internal IP, the users will resolve the mail server correctly but will also be able to resolve the "www" and "ftp" and other "domain.com" records properly without you having to do anything.

Dave Shackelford
ThirdTier.net
TrainSignal.com