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I am using RHEL 5 server as proxy server in Local network. Under server i have few windows machines.

Now i want to configure Outlook 2003 for send and receive mails in windows boxes, When i configure and test connections, It showing connection failed.

In browser, internet working well.

Without proxy, windows outlook - 2003 configure well in windows boxes also working well.

What you think about it and How can i solve this problem ?

Please give clear steps to solve.




We hosted a site by website hosting provider, they only providing mail service to us.

It is linux server. They providing smtp and pop3 services.

In my local server i disabled firewall itself .

And by use of advanced port scanner, I scanned my local server from my windows machines, Port for smtp and pop3 's are not opened.

I used iptables also, But ports not opened , And in squid proxy i configured smtp and pop3 ports are safe ports.

Help me to solve it...

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You say Outlook Express, but your tag says Outlook 2003. Which version are you actually using? – MDMarra Apr 5 '10 at 5:12
Your edit still does not make sense. There is no Outlook Express 2003. You're either using Outlook Express or Outlook 2003. Outlook Express came free with versions of Windows before Vista. Outlook 2003 comes with Office 2003. – MDMarra Apr 5 '10 at 12:10
up vote 2 down vote accepted

Using Squid, IPtables automatically blocks internet traffic, you'll need to unlock it from iptables.


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Are you trying to connect to a POP3 or IMAP server through your RedHat server's proxy? I'm assuming you're running Squid, and as far as I know, it's an HTTP proxy, not a SOCKS proxy, so you won't be able to use it to connect to a remote (Internet) POP3/IMAP server. I would just connect directly without the proxy from Outlook.

If you want to proxy all outbound connections, you might want to look at Dante proxy or tinyproxy:



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@gravyface, How can i connect directly without the proxy from Outlook ? – Kumar Apr 6 '10 at 6:41
Are you running Squid in transparent proxy mode? My default, it should only intercept HTTP (port 80) or HTTPS (443) requests; it should have no impact on you directly connecting to your POP3/SMTP server on the Internet. Try this: from your machine, start -> run -> cmd then: telnet 25 and likewise for telnet 110. – gravyface Apr 6 '10 at 16:49

A others have said, Outlook Express and Outlook 2003 are quite different things, so you should clarify.

But the most important clarification needed here is: what kind of mail server are you trying to connect to?

If it's a standard POP3/SMTP (or IMAP/SMTP) mail server, Squid definitely can't help you here, and you should look instead at your networking and firewall configuration.

Your web proxy would be involved only if you are actually using Outlook 2003 to connect to a remote Exchange server via RPC/HTTPS (aka "Outlook Anywhere").


Looks like you're trying to connect to a POP3/SMTP mail server; that's ok, but then you should tell us more about your network configuration.

Where is the server you're connecting to?
How is your network layed out?
How do you connect to the Internet?
What router/firewall/NAT are you using?

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