Firewall Wizards mailing list archives
RE: POP vs IMAP vs MAPI - security through firewalls?
From: Ben Nagy <ben.nagy () marconi com au>
Date: Mon, 26 Feb 2001 13:44:44 +1030
You might like this link: http://www.microsoft.com/ISN/faq/ports_used_nt_and_exchange.asp To summarise: - I don't think any M$ stuff uses port 136 for anything at all. - I don't think any M$ stuff uses 137/138 _TCP_ for anything. UDP is used on these ports for all sorts of nasty, NASTY stuff that a) has nothing to do with getting mail to work and b) is BAD to pass through a firewall. - I can't see any reason why you'd want port 139 TCP to work, either, but I could be wrong. AFAIK, you _should_ only need to open port 135 for RPC and some dynamic ports, ala KB article Q270836. This may be where they get 50000 etc, but the recommended range is 1024 - 5000, so who _knows_ what's going on. That doesn't help you with your security comparision, though, sorry. I wasn't aware that _any_ of those protocols were "secure" - they're all cleartext, for a start. Since all the TCP connections are _supposed_ to come from the inside outwards, though, I don't see _too_ much exposure from the protocol level. It's a matter of guessing which implementation is most likely to be buggy, I suppose. Toss a (three sided) coin? (Neater solution: Run a Citrix box outside the firewall, run the ICA client on your SUNs and then use Citrix sessions to read mail. Solves two problems at once.) Cheers, -- Ben Nagy Network Security Specialist Marconi Services Australia Pty Ltd Mb: +61 414 411 520 PGP Key ID: 0x1A86E304
-----Original Message----- From: Joseph S D Yao [mailto:jsdy () cospo osis gov] Sent: Friday, 23 February 2001 8:36 To: firewall-wizards () nfr net Subject: [fw-wiz] POP vs IMAP vs MAPI - security through firewalls? Recently, one of our firewalled sites (hosted at a military base) was directed that they had to stand down their internal mail server and use the external base mail server. This being the US military, this will be an MS Exchange server, and the people inside the firewall are being directed to use MS Outlook. [How this will run on their Suns I don't know, but that's not my problem.] They were told they had to use MS MAPI to read the mail, and so they would have to open TCP ports 135-139, 50000, 50001, and perhaps others to be named later. They were also told that MAPI must be used because it is "slightly more secure" than POP3 or IMAP4. The firewall is proxying-only, which of course means TCP-only. I'm not familiar with MAPI, and of course there is no RFC describing it, or any publicly available documentation of which I'm aware. Is anyone aware of any verifiable security testing that's been done on MAPI? Is it in fact "more secure" than POP3 and IMAP4? You needn't tell me that the latter two have security vulnerabilities - I've heard this - but details would help [I haven't collected those], and if there is a comparison to MAPI that would be so much the better. Is MAPI that much better? [It had better be, to use up 7+ ports! ;-(] Are there any reliable proxies for any of these protocols? Thank you! -- Joe Yao jsdy () cospo osis gov - Joseph S. D. Yao COSPO/OSIS Computer Support EMT-B -------------------------------------------------------------- --------- This message is not an official statement of COSPO policies. _______________________________________________ firewall-wizards mailing list firewall-wizards () nfr com http://www.nfr.com/mailman/listinfo/firewall-wizards
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Current thread:
- POP vs IMAP vs MAPI - security through firewalls? Joseph S D Yao (Feb 25)
- RE: POP vs IMAP vs MAPI - security through firewalls? Chris Crozier (Feb 26)
- Re: POP vs IMAP vs MAPI - security through firewalls? Joseph S D Yao (Feb 26)
- Re: POP vs IMAP vs MAPI - security through firewalls? Michael Nelson (Feb 26)
- Re: POP vs IMAP vs MAPI - security through firewalls? Patrick Darden (Feb 26)
- Re: POP vs IMAP vs MAPI - security through firewalls? Rick Murphy (Feb 26)
- <Possible follow-ups>
- RE: POP vs IMAP vs MAPI - security through firewalls? Ben Nagy (Feb 26)
- Re: POP vs IMAP vs MAPI - security through firewalls? Joseph S D Yao (Feb 26)
- RE: POP vs IMAP vs MAPI - security through firewalls? Jan van Rensburg (Feb 26)
- RE: POP vs IMAP vs MAPI - security through firewalls? Chris Crozier (Feb 26)