I'm having an issue with the diagnostics system at mxtoolbox. I'm also having an issue with yahoo.com hotmail.com emails not being delivered (bouncing). They are being bounced back "Mail server for "hamiltonwildcats_com" unreachable for too long".

I think the two issues are connected but I can't seem to fix the problem.

My server IP: 67 214 181 213
SMTP host: mail_hamiltonwildcats_com

I'm running CentOS 6.3 with Exim 4.76 under a DirectAdmin environment.

When I run your diagostic test on my server I get: 11/24/2012 11:07:46 PM Connection attempt #1 - Cannot access a disposed object.
Object name: '' ''. [16.22 sec] when I run it on the IP address and:

11/25/2012 4:24:32 PM Connection attempt #1 - Timeout occurred due to inactivity. [16.22 sec]

When I run it on the hostname mail_hamiltonwildcats_com.

I read something on the mxtoolbox forum for someone else that had the same issue. It indicated that their SMTP Banner was taking 30 seconds to show which was too slow. I have connected to my SMTP server via telnet on port 25 and the banner is displayed immediately. I ran a HELO command and the response was immediate. When I connect to my server with telnet via port 25 it also shows the smtp banner as soon as you connect.

I don''t know what exactly the problem is so I would greatly appreciate your help is figuring this out. could you please help?

I can send emails to hotmail and gmail and yahoo if the emails originate from the local host. However if they originate from an external ISP mail server then they don't get delivered. If I send an email to one of those email addresses and then the recipient replys then that reply message will bounce 24 hrs later.

I'm lost on how to debug this and would appreciate any help I can get please.

I just tried connecting using telnet and did not get a greeting.
Are you running the test on the same server? If so, try from a remote client. You may have a firewall issue.

Okay... I opened port 25 on my firewall. Would you mind testing again?

Maybe it was letting me through because I was testing from my home desktop and that IP address is whitelisted in the firewall.

telnet: connect to address xx.xxx.xxx.xxx: Connection timed out

Tried it from a different server and it worked. I think my home ISP is blocking outbound to port 25.

Does rogers, yahoo or Gmail check port 25 before sending a message to an address on that same server.