Can send but can't receive external e-mail

[davidelon]

Hi Everyone,
i installed the ZCS 6.05 in a ubuntu server 8.04 LTS.
everything gone right, even the installation of BIND9.
i can succesfully send e-mail (ex from user@mydomain.it to user@gmail.com)
but if i reply from @gmail to @mydomain, i can't receive anything.
I have not a static ip address, but a dynamic ip address. Maybe my isp is blocking me?
Thank you for your reply (i'm sorry for my english but i'm italian )
DAvide

[quietas]

You'll need to check MX records for your DNS registrar. If you are using a dynamic IP, you'll need to sign up for a static or setup a Dynamic DNS host such as DynDNS or No-IP and then pay a small amount for the MX capability.

Also check that your ISP is not blocking port 25. If they are, most DDNS hosts can also do port forwarding so port 25 sends to port 2500 or something like that.

[davidelon]

thank you for your reply quietas.
I have a record A for my mailserver (mail.mydomain.it) and its assocciated MX record.
I even have an account for No-Ip, in fact i can reach the webmail with the dns redirection provided by no-ip.
I have one question: in my dns control panel, i need both A record and MX record ? or I can add A record and then go to no-ip and add an MX record?
then, how can I check if my isp is blocking port 25 ?
thank you
DAvide

[quietas]

It sounds like port 80 is fine if you can get to the webmail portion. You will need both A and MX records setup at No-IP so the outside world knows where the server is located and where to send the mail to.

If you are on a compuer behind the firewall with that IP, go to **Home of Gibson Research Corporation** and use the Shields UP tool to scan you IP for open ports. There are other IP scanners out there which can scan for open ports on specified IP addresses also.