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Bill wrote: > Hi, > > Could be worth stopping the local instance of exim to allow you to > forward local:25 to remote:25 to see if the change of port is upsetting > the remote exim. > > It is very strange. > > Bill > > > Grant Sewell wrote: > >> Hi Bill, >> >> The confusing part for me is why the forwarding of local:26 to >> remote:25 through my ssh tunnel doesn't seem to work when using PuTTY >> through an MS-ISA proxy even though the forwarding of local:143 to >> remote:143 does (through the same tunnel). OK, forget the proxy - I >> just managed to recreate the problem without being at College. I used >> the same PuTTY profile as I do when I'm at College, but removed the >> proxy information. It brought up a command-line fine, imap works fine >> but smtp still doesn't. >> >> Here's my "sudo nmap -v localhost" >> Starting Nmap 4.53 ( http://insecure.org ) at 2008-11-23 09:20 GMT >> Initiating SYN Stealth Scan at 09:20 >> Scanning localhost (127.0.0.1) [1714 ports] >> Discovered open port 25/tcp on 127.0.0.1 >> Discovered open port 22/tcp on 127.0.0.1 >> Discovered open port 26/tcp on 127.0.0.1 >> Discovered open port 445/tcp on 127.0.0.1 >> Discovered open port 139/tcp on 127.0.0.1 >> Discovered open port 143/tcp on 127.0.0.1 >> Discovered open port 5432/tcp on 127.0.0.1 >> Discovered open port 5900/tcp on 127.0.0.1 >> Discovered open port 631/tcp on 127.0.0.1 >> Completed SYN Stealth Scan at 09:20, 0.15s elapsed (1714 total ports) >> Host localhost (127.0.0.1) appears to be up ... good. >> Interesting ports on localhost (127.0.0.1): >> Not shown: 1705 closed ports >> PORT STATE SERVICE >> 22/tcp open ssh >> 25/tcp open smtp >> 26/tcp open unknown >> 139/tcp open netbios-ssn >> 143/tcp open imap >> 445/tcp open microsoft-ds >> 631/tcp open ipp >> 5432/tcp open postgres >> 5900/tcp open vnc >> >> Read data files from: /usr/share/nmap >> Nmap done: 1 IP address (1 host up) scanned in 0.265 seconds >> Raw packets sent: 1714 (75.416KB) | Rcvd: 3437 (144.372KB) >> >> So nmap shows that local is accepting connections on :26, but it can't >> identify the service. Incidentally, the output is identical, even >> when it does work. >> >> "telnet localhost 25" gives this: >> Trying 127.0.0.1... >> Connected to localhost. >> Escape character is '^]'. >> 220 hplaptop ESMTP Exim 4.69 Sun, 23 Nov 2008 09:26:55 +0000 >> >> Whereas "telnet localhost 26" gives: >> Trying 127.0.0.1... >> Connected to localhost. >> Escape character is '^]'. >> Connection closed by foreign host. >> >> When using the command-line version (and therefore 26 --> 25 port >> forwarding works), it gives this: >> Trying 127.0.0.1... >> Connected to localhost. >> Escape character is '^]'. >> 220 server.thymox.co.uk ESMTP Exim 4.63 Sun, 23 Nov 2008 08:49:37 +0000 >> >> I've attached the saved Wireshark data from an unsuccessful connection >> to localhost:26, in case it is of any interest. >> >> Cheers. >> Grant. That's just it... it doesn't. Right now (as in *now*) I am at my girlfriend's house using my ssh command-line (as in the first email) to forward local:26 to remote:25, and it works wonderfully. It is *only* when I use PuTTY to do so that it fails, and yet PuTTY forwards 143 flawlessly. Essentially, the remote end (ie the server) shouldn't be aware that I'm using :26 on the laptop as all the traffic it sees will be received on :25, as per a normal connection. Grant. -- The Mailing List for the Devon & Cornwall LUG http://mailman.dclug.org.uk/listinfo/list FAQ: http://www.dcglug.org.uk/linux_adm/list-faq.html