Port 22 blocked?

two_sevens_clash · 12-07-2005, 12:54

Hello,

I am a web developer and use SSH/Telnet to access our web server. Over the past few weeks I've been unable to connect except for very brief periods. The normal response is 'error: the network connection has timed out' indicating that the server is uncontactable.

The server is actually fine and I can reach it by pinging, ftp (port 21), http (port 80) and mysql (port 3306). Only on port 22 do I have this problem. Other users of the server can connect using this method with no problems.

I have checked and disabled all firewalls and connected to the cable modem directly (I normally use a Netgear 4-port broadband router). This is also not a PC problem as it occurs on all machines I have at home (none of which have firewalls installed).

Does anyone know if NTL is blocking this port? Is anyone else aware/experienced this problem? I think it may be at their end but I haven't been able to find any information about this.

I have also asked this question on ADSL Guide - they pointed me to the information in the link below showing which ports NTL blocks. Is it the case that 22 has been added to this list?

http://www.adslguide.org.uk/newsarchive.asp?item=1729

Thanks in advance,

Paul.

Toto · 12-07-2005, 13:11

No, ntl do not block this port.

I can access port 22 from a number of different IP addresses on ntl's network.

The list you have has not been added to as far as I can tell.

Oops

to the site

two_sevens_clash · 12-07-2005, 13:28

Thanks, Toto!

That's very interesting. The problem for me only seems to have occurred after an upgrade to the 2Mb service about three months ago. I have tried rebooting the NTL modem several times since to get a newly assigned IP address but it hasn't made any difference.

Well, at least there's a hope of being able to work again! I guess I'll have to investigate my home setup some more....

Thanks for your help,

Paul.

Nemesis · 12-07-2005, 13:48

Is it possible that there is a problem with the firewall on the server you are trying to connect to.

Can you reach Port 22 on any other server ?

two_sevens_clash · 12-07-2005, 14:11

Hi Simon,

We actually use two Linux servers (albeit hosted by the same company) and I can reach neither via SSH on port 22. They are two separate machines with different IPs so that's why I was suspecting NTL as stopping this traffic.

My colleague who works on the server at a different site can connect fine so the port is not blocked server-side. Linux is not my strongest point but I don't believe there are any ip-specific blockages either. Also suspect is the fact that I could connect OK over a two-day period (without any adjustments to the server or PC) but then reverted back to its old behaviour.

I may try a dial-up connection to see if I can access the server this way. Back to the old school, eh?

simbr · 12-07-2005, 14:20

Are you connecting using a STB? I seem to recall there being a problem using some ports on a Samsung box.

two_sevens_clash · 12-07-2005, 14:38

Hi Simbr

No, I'm using a standard cable modem (an ntl:home 120 I think). Thanks for the information though!

Is there any way to check the configuration of this device? Couldn't find much on the NTL site.

Nemesis · 12-07-2005, 14:40

If you are confident that the server(s) are not IP blocking you, then i would suggest a firewall issue. Are you using the windows firewall, or another sotware firewall. If so they will need to be turned off, and often uninstalled to see if it is them causing the problem.

two_sevens_clash · 12-07-2005, 15:13

That was my instinct as well! I have turned off the Windows XP SP2 firewall and do not have any other firewall software installed (at least as far as I know). I have also checked my Netgear router config and made sure that there were no ports blocked or port-forwarding enabled. The only device I am not sure about is the NTL modem.

BTW, have also ran spyware and trojan software just to be sure - all came out clean (bar some tracking cookies).

I'll have another check, though. It definitely has all the hallmarks of a firewall problem...

Nemesis · 12-07-2005, 15:14

Can you connect directly to the modem for these tests ?

two_sevens_clash · 12-07-2005, 15:52

Yep, good idea - at least that will take the router out of the equation. I'll let you know how I get on. Many thanks to everyone who has helped so far

simbr · 13-07-2005, 07:06

ductape uses ssh.. try connecting to ductape.net on port 22 and see if you get a login prompt.
What client are you using? Have you tried using another one (e.g. putty)?

two_sevens_clash · 13-07-2005, 09:48

Thanks Simbr, Ive been looking for another SSH server to test so I'll give Ductape a try. I actually use putty and a deriviative of it in the Tortoise CVS software. I haven't tried another client - I understand that putty is pretty much the standard software for this sort of thing.

No luck again last night but my attention was mainly on one of my PCs failing

. I'll give it a more thorough test later!

simbr · 13-07-2005, 12:29

You could try typing "telnet <server> 22" in the run dialog, you won't be able to log in since the procol will be wrong but it'll show if you can get through on port 22 at all.

carlingman · 13-07-2005, 23:30

Quote:

Originally Posted by two_sevens_clash

Thanks Simbr, Ive been looking for another SSH server to test so I'll give Ductape a try. I actually use putty and a deriviative of it in the Tortoise CVS software. I haven't tried another client - I understand that putty is pretty much the standard software for this sort of thing.

No luck again last night but my attention was mainly on one of my PCs failing

. I'll give it a more thorough test later!

I think I will

off now as am starting feel old here as I remember putty and ductape used to hold windows together and I am not talking about Mr Gates Windows either.