Could not send/receive emails from outlook express though ISA server

Posted on 2005-04-16
Last Modified: 2008-02-01
Hi experts,
  I have setup a domain with a child domain and clients. My DC use  windows 2000 server OS. I also have a windows 2000 advanced server machine. I loaded ISA server on this machine. This pc acts as a multihome pc, where i configured two network cards. One network card for internal connectivity and the second one for internet connectivity. I assigned my gateway and ISP DNS name in the adapter which is connected to my DSL router. For the internal adapter, i have assigned  one internal ip address and DNS address is loopback address ( In ip packet filter option i enabled most of the required protocols. Now I am able to connect internet from all cleints. But the problem is that i am not able to send or receive emails from my mail clients (Outlook express ) or (Microsoft Outlook). Could anybody help me out as i am struggling with this problem for the last one week
Question by:pvraj
    LVL 1

    Expert Comment

    Hi Pvraj,
    I assume your clients are accessing an internet mail server which is not in your private network.
    Want to find out if it is the ISA policy issue or other issue. Are you accessing your email server thru pop3, if so are you able to get respond by telnet "email server" 110? and also port 25? from your clients?
    Try to figure out if it is the ISA blocking the ports...
    LVL 12

    Expert Comment

    If the mail is on secure sockets, the ports will be different.

    There are also other issues.  For Exchange and Outlook, they will try to authenticate to the smtp mail server, which, if is just port 25/110 and upstream, will not require it.

    First, your network setup:  what are the mail servers?  do you have local mail servers as differentiated from internet mail servers?

    Mail from internal servers is usually sent using user@hostname.domain.tld and not just user@domain.tld

    Additionally, the mail server is hostname.domain.tld and not the smtp external server.

    What are your incoming and outgoing mail servers?

    Author Comment

    Hi experts,
      I dont have any dedicated email server in my network setup. Basically it is the ISP's email server i am trying to access. i have only ISA server running on windows 2000 advanced server as  i told before. though i am able browse frm my clients using internet explorer, Could not download emails using outlook. I am getting a message which sounds like, client machine is not able to reach the ISP email server...

    LVL 12

    Accepted Solution

    Then you have to forward it from one of your mailservers to your ISP's mailservers and unless you have a business account and a static IP they probably won't relay email outside of your personal email addresses.

    Although I do have all of the required stuff, my own email servers, business account, various domains and servers, I'll tell you how I can forward and relay, but only through my own Busienss Static IP Addresses [which go through my ISP because all they supply is the pipe].

    I use Linux as a FrontEnd Server for XP, NT, and other servers and boxes.  On one XP Home box I have MailEnable installed.  The Linux box is the gateway to the Internet, via upstream ISP, and the Windows Servers and boxes feed through the Linux box, or a router, under Linux control.

    So MailEnable, on a simple XP Home box acting as the mail server for local network to Internet, and Internet to local network, has the mail server as, let's say,

    When it sends email out to the Internet, it sends it as which shows up as once it passes through the Linux Server and on out to the static IP on an unblocked port.  Were I to try and use the ISP's mail server, I would get Relay Denied. I don't because my setup is legitimate [the benefit of having your own real domain and a static IP with a business account].

    Unless you have a business account, you may already be in violation of the ISP's Terms of Service by running a Server through a residential network out onto the Internet.

    Even if you get it working, you should really look into getting the proper setup and account, before you get yourself on a spam list.

    It used to be you could do all those things without such credentials, but then people abused it, some still are, and thus, the ISP's shut down the mail relays.

    You can only send email currently using your ISP username account and password.  You cannot forge a domainname either.  You have to Register a real domain, what they call a Fully Qualified Domain Name [FQDN].  From there, you have some work to do.  Offers for free domains, free DNS, and free email servers are bogus.  They are "all" recognized as the major source of spam, currently the U.S. is the biggest spammer with over 50% of all the spam email in the world coming from the U.S.

    You have the luck to have the Servers.  Now invest in making a real domain and network.

    Expert Comment

    i have a linux router/proxy but I cant download mail from a mail server on the internet using outlook express on client machines..
    I can access internet from these clients though...
    I am not running any firewall or iptables
    what can I do..???

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