FW: [IMail Forum] IMAIL- dns problem?

[David Richardson]

Title: Message

Wow!  Thanks to everyone for all the insight.  Yes, I assumed it was probably a firewall "looping" issue.

 

I checked server A, it already had a Hosts file.  I added the entry with the private IP for "epage.gabrielwireless.com".  Now my messages are making it to that server.  That's good!

 

Yes, everyone was correct- I could telnet to the private IP's, but not the public ones between the two servers.

 

So, now I just need to finish the hosts file but i have a few questions.  First, on Server B, it is also my DNS server, there is not a HOSTS file or ETC directory under system32.  Can I simply add one? 

 

On Server A's hosts file, I am unsure what entry I should put:  for example, for domain www.gabrielwireless.com, I have the DNS MX record to "Mail.GabrielWireless.com" and the corresponding IP.  There is also an A record for "mail" and then there are A records for "WWW" and some others.  Do I enter a single line with the private IP then the "mail.gabrielwireless.com", or do I enter multiple lines - one for each possible combination of the domain header?  Or , can I simply add a line with the domain listed as "gabrielwireless.com" and that would encompass them all?

 

Thanks,

David

 

 

-----Original Message-----
From: Mike Barber [mailto:[EMAIL PROTECTED]
Sent: Wednesday, July 23, 2003 9:49 AM
To: [EMAIL PROTECTED]
Subject: RE: [IMail Forum] IMAIL- dns problem?

It might be your NAT causing you these problems.

 

Some NAT / Firewall type devices will not allow a connection to "loop" (Come from inside the NAT connecting to a public IP address on the NAT Device and that public IP routes back inside the NAT), From the log you posted it looks like that may be the problem

 

Try using telnet from a command prompt and see of you can connect to the 216.199.154.53 IP address on port 25 from your IMail server.

Then see if you can telnet to it's Private IP address on port 25

 

If you can't connect to it's public IP address but can connect to the Private IP then it is probably your NAT Device.

Check the Manual, for your NAT

Make an entry in your hosts file for the mail servers to override DNS (make the entry for the host point to the private IP address)

 

If you can connect to both Public and Private IP addresses to your mail servers from your mail servers then it would be a DNS issue

 

 

Mike Barber

Software Tester

Ipswitch Inc.

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of David Richardson
Sent: Wednesday, July 23, 2003 9:16 AM
To: [EMAIL PROTECTED]
Subject: [IMail Forum] IMAIL- dns problem?

Hi everyone, I am using Imail v6 on two separate servers in my office.  They have been running for several years now without problem.

Over the weekend, I switched my entire network from a DMZ with public IP's on the servers to a NAT'd network with private IP's on the servers, but with static destination-nat routes for each DMZ server.  Everything works fine- the Imail servers can send and receive emails from anywhere on the net.

Only problem is when I attempt to send a message from one account on Imail server A to an email account on Imail server B.  It will fail.  As well, if I try to send a message to another server within the same network (not an Imail server, but an email receiving server) I also fail.  Now, all 3 machines accept messages from the outside world just fine.  It's only when I'm trying to send messages internally that they fail.  This was never a problem before.

In the logs, I just get:
20030723 084428 127.0.0.1       SMTP (147) Trying epage.gabrielwireless.com (0)
20030723 084507 127.0.0.1       SMTPD (00A2011A) [10.1.1.10] connect 10.1.1.10 port 3525
20030723 084513 127.0.0.1       SMTP (147) MX connect fail "216.199.154.53"

This is when I try to send a message from the Imail server A to the third (non-imail) email receive server.  When I try to send a message from Server A to Server B (both Imail) I find no record of anything in the logs- I just get back an undeliverable message- delivery failed after 10 attempts.

I suspect a DNS problem.  I have a DNS server on the same network as the other 3 machines. I have tried using as the DNS server SMTP value- both my private DNS server's IP and the public one, neither makes a difference.   So, as a test, I set the DNS settings in the Imail servers to a DNS server off my network, no difference.  Still fails. 

Any ideas?  Thanks in advance, and sorry for such a long email.

David Richardson
Gabriel Wireless - Florida
www.gabrielwireless.com