*** DNS and Reverse DNS Problem ***

[jonnywah]

Our outgoing email uses the DNS servers from GoDaddy. Our domains use the DNS server from ZoneEdit.

I am trying to set up a mail server at home using SMTP Service in W2K IIS. I have no MX records, CName, PTR, etc. for this server.

The problem is other SMTP servers cannot do a Reverse-DNS so they don't accept email from my mail server at home. Please help. Any suggestions or information would be appreciated.

 

[ChrisAC]

Two choices:

1. Get reverse DNS set up for the IP address of your mail server.

2. Smart Host through your ISP's mail server (presuming that they will let you and that their server has reverse DNS).

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[jonnywah]

Chris,

I need to go with the first option, but I'm not sure how to do this. Please help. Thank you.

 

[WizyWyg]

Contact your ISP, since they are the ones controlling your mail server's IP address.

 

[ChrisAC]

I agreee with WizyWyg. If you have IP addresses from your ISP and your mail server is on one of these addresses then it is most likely that your ISP will have the reverse zone delegated to them and they will be able to create the PTR record for you.

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[jonnywah]

This is for a colocated server. Should I contact the colocation facility??

I am confused. Internet users use Zone Edit's DNS servers to surf to my domains. If I want to send mail out using W2K IIS SMTP service, is the colocation facilities DNS servers responsible for setting up Reverse DNS (PTR records?) for all of my domains??

 

[ChrisAC]

Forget about who is responsible for the domain names. This has nothing to do with what servers resolve which domain names. Reverse DNS uses a special zone file and reverse zones are usually delegated to whoever is responsible for those IP addresses.

So, if you have the domain jonnywah.com and that domain is hosted on the DNS servers for ZoneEdit, it doesn't mean that the same DNS servers are going to be responsible for the reverse DNS.

If your server is on IP address 1.2.3.4 with your ISP then it is most likely that your ISP will have the reverse zone 3.2.1.in-addr.arpa assigned to them. If they do have the zone delegated to them then they would create a PTR record for your mail server. You really should also create a forward lookup on ZoneEdit to match the reverse for servers that do double reverse DNS. In this case they see an incoming IP address and then check the PTR record. Once that has resolved to a hostname they then check the hostname to see if it resolves to the original address.

So, lets say that you call your server web.jonnywah.com. In your zone file on ZoneEdit you would have ..

web.jonnywah.com IN A 1.2.3.4

Now if the IP address 1.2.3.4 belongs to your hosting company then they would create a reverse entry on THEIR DNS servers as such ...

4.3.2.1.in-addr.arpa IN PTR web.jonnywah.com

So the forward zone jonnywah.com is delegated to the ZoneEdit server but the reverse zone for its IP address 1.2.3.4 is delegated to the ISP's DNS servers and so only they can create the reverse record.

Clear as mud?

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[jonnywah]

Chris,

You've been a great help! Thank you.