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Configuring a mailserver - I need some new eyes

Hi all,

I've just configured a new Win2003 Server with MailEnable, IIS and DNS etc etc.

The domain is dee-it.co.uk, it resolves to 84.12.251.85, I've opened the ports on the firewall etc etc, but for some (stupid) reason, I can't telnet to port 25 of the domain name.

i.e.

telnet
o mail.dee-it.co.uk 25

Can I please have someone else's eyes as this thing is doing my head in.......it's taken too long, I've drunk too much coffee and I've gone crosseyed !

Max points here as I just need to get it fixed.
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legalsrl
Asked:
legalsrl
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1 Solution
 
legalsrlAuthor Commented:
By the way, it's not the firewall or AV software (I was using McAfee, but I've configured that correctly - I DO know that)

Si
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TheCleanerCommented:
You can telnet to the IP address on port 25 or no?

Are you trying to do this internally on the domain?
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SanDiegoComputerCommented:
Ok.  Here are my questions:

1. What type of connection is this.  Some providers filter port 25 so that users can't run mail servers on non-business class connections.
2. If you are on that server, can you telnet to 127.0.0.1 port 25.  If so, then the server is not the problem, it's either your firewall is not forwarding or your provider is not forwarding port 25 as per #1.
3. Are any other forwardings working properly on the server (i.e. Port 80 for www)
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legalsrlAuthor Commented:
Hi all,

This is an ADSL Business Connection with a static IP

Port forwarding (80) works fine........

The provider has confirmed that they are not filtering port 25.

Any other ideas guys ?

Thanks for your help
Si
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legalsrlAuthor Commented:
OK,

I've logged on to the server and can telnet to port 25 of the server.

The Server has 2 IP addresses.

192.168.100.247
192.168.0.1

I can telnet to port 25 of both of them from anywhere inside the network

i.e. if I log in as 192.168.100.50 I can telnet to 192.168.100.247
     if I log in as 192.168.0.100 I can telnet to 192.168.0.1

The Firewall is at 192.168.100.7 and has port 25 opened and is directed to pass any port 25 traffic to 192.168.100.247

There is nothing between the server and the firewall to stop any traffic.

Ahhhhhh.....I wonder if I need to add any static routes ?  I'll check, but I don't know.

Thanks guys
Si


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SembeeCommented:
Both of the servers in your MX records aren't accepting connections.

http://www.dnsreport.com/tools/dnsreport.ch?domain=dee-it.co.uk

Therefore it is either port 25 is blocked, or the NAT isn't correct on your firewall.
What is set as the default gateway on this machine? It should be the firewall, with no default gateway configured on the other interface.

Simon.
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legalsrlAuthor Commented:
Hi Simon,

I've been checking the dnsreport for most of the week now, I've spoken with Nildram about 10 times and they confirm that they are not blocking the port.

The DG is the firewall, there is no gateway on the other interface

So presumably it's the NAT on the firewall, but it's passing port 80 ok.

That's what I don't understand........damn this is frustrating !

I've enabled port 21 and checked that it passes it.....it does.......

I've disabled and re-enabled port 25 god knows how many times, so it can't that......

Struggling in Pompey
Si
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SembeeCommented:
Get connected to the same ISP, but outside of your network. See if you can connect to port 25 then.
Yo have mentioned two sets of IP addresses. I am not a great lover of dual homed machines, they usually cause more problems than they are worth. Is SMTP bound to the correct IP address?

Simon.
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legalsrlAuthor Commented:
Hi Simon,

Yes, SMTP is bound to the correct port.

I'm well and truly stuck on this one.

Thanks
Si
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SanDiegoComputerCommented:
Ok.  My next check woluld be in the SMTP service itself.  You can specify if were it will accept connections from.  Verify that it will accept conntections from any ip and any server.  (not relaying)
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TheCleanerCommented:
You said, "the DG is the firewall"....I may be out of it, so what does DG stand for?

What kind of firewall is it?  That would allow us to possibly tell you how to correctly setup the NATing.

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legalsrlAuthor Commented:
Hi all,

Sorry, DG is default gateway.

I'm setting up a 3Com CwrDr100a-7s  as it's my preferred choice of router.

I've made a couple of DNS changes, that I'm sure won't make any difference, but I'll let you know in the morning if they do !

Thanks
Si
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TheCleanerCommented:
Well, I'm not familiar with the 3com devices, but as a general "NAT" setup:

1.  Configure the external facing firewall or router with the IP address of the external IP that is the MX record
2.  Configure the external facing firewall or router to NAT the IP address and port 25 to the internal IP address of the mail server/gateway.

That's a very basic setup though.  If you have multiple routers or firewalls then your configuration may be more in depth.
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