Accessing email server behind firewall

Bridgemics

15 pts.

Tags:

Firewalls

IMAP

LAN

Routers

Routing

SonicWALL

I have an email mail server running on our LAN, it takes emails form various ISPs and sends then to users on the LAN. I want to be able to access this email server via IMAP from the internet so I can see my emails when out of the office. I can set a rule which allows web traffic to a web server but when I use the same type of rule I cannot get to the email server. I redirect IMAP4 requests on port 143 to the LAN IP address where the email server is. I have spoken to the manufacturers of the email server and say that this is possible with their software and no other settings need to be changed. I use mail2web.com to look at my server but I don't get any feedback as to what the error is, just that there is an error. Can anyone help? Perhaps any software which might indicate where the error is.

Asked: September 3, 2008 4:42 PM Last updated: September 4, 2008 3:17 PM

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Last updated: September 4, 2008 5:53 AM GMT

Denny Cherry68,390 pts.
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- Denny Cherry68,390 pts.

Thanks. We'll let you know when a new response is added.

Have you tried connecting to the mail server with a regular IMAP client? This will tell you if it is working, or if not what the error message is.

Without the error message finding the problem will be next to imposable.

Discuss This Question: 2 Replies

Bridgemics Sep 4, 2008 3:11 PM GMT

Sorry if this reply is in the wrong place I didn't really understand the format of this system Anyway, I don't have a way to do this. If I connect from within my LAN I have no problems. I don't have another PC on the internet with a standard IMAP client to try to make the connection. Since the original post Ihave removed the firewall entirely and still get the same problem, so I guess it is either the email server software or the windows 200 software. I am still trying so any more ideas would be great.

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petkoa Sep 4, 2008 3:17 PM GMT

Hi Bridgemics, I think first of all you have toensure you are reaching yor imap server. If you have a linuxbox ready, hping2 is what you need. If you have no linux box, get a live CD with a rescue linux distribution (I, personally, use insert - http://www.inside-security.de/insert_en.html - or grlm - http://grml.org/ ), and hping tcp port 143 with SYN packets. If you don't get SYN ACK packets back, trace the route for this kind of packets (man hping describes all necessary options). If you have any issues with hpinging, resolve them and then try to "telnet imapserver 143" - telnet can serve as a basic client for any protocol - and get any error messages. It is possible (and very probable) that imap server can be reached from outside LAN only using tls encryption. In this case you have to set appropriately your real imap client. Good luck, Petko

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