I can send mail, but cannot receive mail in exchange

[Nunezy]

Hello all,

I have a problem in Exchange 5.5 where I all users can send mail in house and receive mail inhouse.

Mail that is sent out on the internet works to but we cannot receive mail.

I know of this problem usually relating to DNS but hour DNS seems to be fine as been told by the ISP provider.

We run our own mail server and only use the ISP provider to connect our ADSL line.

Please help.

 

[brontosaurus]

it's either a problem with your MX record, or a config problem on the server itself. Has anything changed on the server recently? May I ask what your domain is to check the MX record?

 

[Nunezy]

Thankyou for replying,

our domain is latitudes.pt.

Sorry as Exchange is new to me so I have been thrown in the deep end to help out.

I don´t think we have a fixed IP either as when I put in

http://www.latitudes.pt

i get no display of an IP address.

Once again I want to thankyou for your help on this matter.

 

[brontosaurus]

actually, your

http://www record

looks fine, as does your MX record. however, I can't telnet to your mail server on port 25. Let's talk about your network, do you have a firewall and/or router protecting you from the internet? Is that firewall/router allowing SMTP connections to your mail server?

 

[Nunezy]

Thanks for your reply again,

I should give you some more background info.

What seems to happen is that sending out is no problem. Receiving from the outside world is.

We do have a router, but sure on the firewall side. I believe the firewall only exists on the ISP provider in who we leased the ADSL line.

I am thinking email issue maybe be a timing out problem somewhere, not sure?

Other info that I am getting is that emails sometimes arrive straight away and on time, but very rare, we receive mails 3 days late or don´t receive them at all. They dissappear. I check the mail queues and they are empty so it isn´t getting stuck trying to convert POP3 mail to SMTP or other protocols. Strange Could this be a problem on the ISP side as we don´t have a fixed ip?

Once again thankyou.

 

[brontosaurus]

It's absolutely timing out, the question is why? It's hard for me to determine because your ISP is stopping ICMP traffic at one of their routers, so my traceroutes fall short of your mail server. However, I have no problem getting to your website. This is what leads me to believe that your ISP is blocking inbound traffic on port 25 and/or port 110.
The fixed IP thing would only be an issue if your ISP were unable to update their DNS records in a timely manner. Right now, DNS is telling me that your mail server is at 195.23.58.42. If that's correct, it's not a fixed IP issue. I would contact your ISP on the blocking things....

 

[Nunezy]

One more thing that I remembered.

When people email in to us, not all the time, but sometimes they receive the message "mail could not be delivered" It is one of those typical router mail messages when you type in an incorrect address. Could this be a addressing issue, again bringing me to believe some type of DNS confusion on the ISP side. What do you think?


Thanks again

 

[brontosaurus]

I think we posted at the same time, so see my prior post. That error message is most likely due to the same problem I have with your mail server...I simply cannot establish a connection on port 25.

 

[Nunezy]

Once again thanks for the response.

You are right on to say that the port is on 25. From our network I can telnet to 195.23.58.42 on port 25.

This must be a block from the outside world from what you said in regards to the ISP blocking the ICMP traffic.

Problem is getting it through the ISP provider to say it is a problem on their end.

Thanks once again.