Networks
I got a Fedora-4 proxy server which has squid and iptables. How do you let the lan users to use their outlook clients to retrieve mails from a remote server (not in our lan). the linux server just does not permit pop3 or smtp. i have opened the iptables completely, tried the xinetd.
any ideas.
Is the remote server also Fedora Core 4? If you opened iptables completely, you should be able to send any requests from your LAN. Even without opening iptables completely, you should be able to send out POP3 and SMTP packets, unless it is explicitly forbidden in iptables.
When iptables was active, did it allow outgoing HTTP requests?
Are you sure your Fedora-4 proxy server is the gateway for the workstations running Outlook?
Are you sure your Fedora-4 proxy server connects directly to the internet, without passing the traffic via a router or another firewall of some sort?
Can users in other LANs or in the internet in general access the remote mail server? Can you telnet to port 110 or 25 on that server from outside your LAN?
If the remote server is running Fedora Core 4, are you sure POP3 has been enabled in /etc/dovecot.conf (if it is running Dovecot)?
by x10nd
1. The remote mail server is not known.
2. http requests were allowed when iptables was active, we use squid.
3. the proxy server connects to the router, the router permits pop3 and smtp traffic. there is no firewall currently.
4. they cannot telnet to port 110 or 25 it just does not happen. i can telnet to port 110 and 25 once connect outside the proxy server.
5. is it dovecot.conf or xinetd.conf. if its xinetd.conf it doesnt work when activated, not sure why when i put in the entries.
the mail server is accessible if not connected to the proxy server.
1. Have you tried telneting to the remote mail server? telnet {server name or ip address} 25
The banner should have some information.
4. When you say you "can telnet to port 110 and 25 once connect outside the proxy server", what do you mean? In other words, can you telnet to the two ports from a workstation inside your LAN, or from outside your LAN? What is the gateway address of that workstation - the proxy server or the router?
5. When I mentioned dovecot.conf I meant the IMAP/POP service in the remote email server. That entry is obviously irrelevant if you say that the remote service supports POP3.
When you say "the mail server is accessible if not connected to the proxy server", what do you mean precisely? Your POP3 and SMTP do not have to go through the proxy server, unless it runs some sort of mail proxy, too. In that case you should look at the configuration of the mail proxy. As far as I know, having installed squid and support it in production, squid caches only HTTP traffic. I assume your workstations are PCs running Windows: you point the workstations to the proxy in Control Panel Internet Options - Connection, but the POP3 and SMTP traffic are directed in the TCP/IP settings according to the entry in 'Gateway' to either your proxy server, if your Fedora 4 server acts as the firewall of all the incoming packets from outside, or to your router which, depending on the model, may also have firewall capabilities.
If you turned iptables off, you can be in trouble very soon if the network is exposed.
By the way, do the email clients specify the IP address or the domain name of the remote mail server? Your problem may caused by a problem in DNS lookup as well.
by x10nd
telnets do not work from inside the lan nor works from the proxy server to the remote mail server. teleneting from a windows machine works.
the clients have remote mail server ip, now dns lookup is a prob how do i get over that.
i donot have a mail proxy, suggest one please.
You say that telnet does not work from inside the LAN nor from the proxy server. In the next sentence you say that telnet from a Windows machine works. Where precisely is the Windows machine where telnet works? Inside the LAN or outside it?
Usually the mail server's IP address is used in the server settings of the email client if the PC is not allowed to have access to DNS lookup, in other words, if the client PC users are not allowed to browse the internet. Is this the case in your organisation and this particular LAN?
If your users are expected to have browser access, adding a valid DNS server entry in their Network properties should fix the problem with DNS. If, on the other hand, it is your organisation's policy not to allow users to browse the internet, you should just leave DNS disabled.
You may not need a mail proxy server. A mail proxy application is part of a firewall software application or an appliance-based firewall like WatchGuard Firebox. A mail proxy accepts connections from external email servers, protecting your server from direct connections from the internet. If you do not run your own mail server, normally you do not need a proxy server.
It sounds as if you would need to contact a network specialist in your organisation or a local network contractor, if available, to look at the way your network has been configured. It would help the specialist or consultant to have some documentation about your LAN.
You should not leave the LAN without firewall much longer.
by x10nd
Sorry about the confusion..
The windows machine is not connected to the proxy server.
i just want the users behind the proxy to connect to the remote email server using outlook.
the lan is protected with iptables. when i said i removed the iptables, it was to test if that was the problem.
now in the outlook mail server entry for POP / SMTP is it the proxy server ip or the email server ip ( i have given the email server ip)
by x10nd
Sorry about the confusion..
The windows machine is not connected to the proxy server.
i just want the users behind the proxy to connect to the remote email server using outlook.
the lan is protected with iptables. when i said i removed the iptables, it was to test if that was the problem.
now in the outlook mail server entry for POP / SMTP is it the proxy server ip or the email server ip ( i have given the email server ip)
by x10nd
Did the outlook client bit, but still it does not get through the box
it says cannot find smtp and pop server
im confused now :0
When you say "still it does not get through the box it says cannot find smtp and pop server", what is the TCP/IP default gateway in that particular client PC? Is it your HTTP proxy server which is also acting as a firewall or perhaps some other firewall or router in your LAN?
What IP address does your Fedora proxy server use as its default gateway? I may be wrong but I believe your LAN workstations should be using the same default gateway. If you do not know what it is, you can check it by using the route command at the command prompt of the Fedora server.
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