IIS cannot send e-mail- stuck in queue- Firewall Issue?

Posted on 2007-08-08
Last Modified: 2008-02-01
Hello Everyone

We have a Windows 2003 web server in a dmz- access is controlled via a TZ170 Sonic firewall. I have a simple asp web feedback form which will automatically send mail to a designated address in the company. I have tested this app on an internal (Lan) based 2003 server with the IIS Virtual Server and it works fine. However on the dmz server the mail gets stuck in the SMTP Virtual server queue which I think is a firewall issue. Currently the only ports open from the WAN (Internet) to the DMZ is port 80 (for HTTP) and port 25 from the DMZ outbound. The Windows firewall is off- no other software is interfering with the closing/opening of ports. This is contoleed by the Sonic Wall. Could anyone tell me which ports as a minimum require to be opened outbound\inbound to the DMZ server to get this to work? I would also like to know as a minimum which ports require opening inbound for pop3 besides port 110.
Question by:SNHead
    LVL 9

    Expert Comment

    Does the server have access to a DNS server in order to resolve the domain name(s) to which it sends to? Port 110 is enough for POP3.

    Author Comment

    I have opened up port 53 but probably not. At the meoment the ip address of the dmz box is with the gateway set at No entries are in the DNS settings for the network card. How do I give it access to DNS servers- by entering Internet DNS servers in the network card configuration?
    LVL 9

    Accepted Solution

    Yes. If you need to resolve internal addresses, you can also edit the hosts file under system32\drivers\etc

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