Remote Desktop Problem From One Location

Redgie · 16 Dec 2009 at 16:41

Hi there,
I've got a home server, nothing unusual there, and have it enabled to be used via RDP. RDP works absolutely fine from my colleagues houses, my sisters flat, and all of my friends houses, but NOT from my workplace. The only suspicious thing is that both my house and work are on 02 and use the same exchange, one of my colleagues is also with 02 and we have no problems between those two.

I've tried RDPing directly to the IP, tried going onto the router, nothing works, any help would be much appreciated!

Sp00n · 16 Dec 2009 at 16:44

You have port 3389 open to the web? :eek:

Probably work firewall blocking/filtering, have you asked your IT support dept?

Beerbaron · 16 Dec 2009 at 16:45

I use RDP fine and im on 02. Would your work block port 3389 or could it be down to their firewall?

Redgie · 16 Dec 2009 at 16:48

Sp00n said:
You have port 3389 open to the web?

Probably work firewall blocking/filtering, have you asked your IT support dept?

Not blocking it unfortunately, I am in the IT department as it is a PC repair company

The router isn't blocking it and port 3389 is open fine.

Not to do with the firewall either unfortunately.

Sp00n · 16 Dec 2009 at 16:52

I meant... you have 3389 open so anyone can connect? You should lock that down as its a security risk.

Can you telnet to 3389?
Can you RDP to other sites from your work?

Redgie · 16 Dec 2009 at 16:55

Can't telnet as it's locked down, RDPing to other sites from work is fine.

Sp00n · 16 Dec 2009 at 17:05

Telnet is locked down? huh?

Just start > run > cmd > telnet ipaddress 3389

Does it connect?

Redgie · 16 Dec 2009 at 17:08

Nope doesn't work I'm afraid.

mynsa · 16 Dec 2009 at 19:26

what happens if your port scan port 3389 from your work place to your home ip address, do you see TCP 3389 open? You can try this from your firewall, if your firewall provides a shell, and from your workstation - are the results the same?

how do you access your home server - via DNS or directly to the IP. If you do use a domain name to connect to it, does the domain resolve correctly from the DNS servers you reference from work?

Redgie · 16 Dec 2009 at 20:23

Port scanning reveals notihng at all, just bounces back, same with programs like Angry IP Scanner.

I access my server via a DynDNS link but have tried the IP to ensure it wasn't an issue there. The domain name resolves fine.

One thing that might be worth mentioning is that it worked perfectly 2 or 3 weeks ago, then one day didn't, this led me to believe it could be DNS related but unfortunately I just don't know.

Thanks for the help so far everyone!

mynsa · 16 Dec 2009 at 21:28

ok - how far does the traffic get out of your network at work, does your firewall have traffic monitoring capabilities, tcpdump, wireshark or debug ip etc? If so do you see the RDP traffic being put on the wire for your internet link?

Redgie · 16 Dec 2009 at 21:38

I'll check that when I'm in tomorrow thanks. The only tihng I know so far is that it bounces straight off the IP, no connection no pin no nothing, from both my home to work and my work to home, I'll check the stuff you mentioned tomorrow, thanks!

Redgie · 17 Dec 2009 at 16:04

Ran a tracert on the IP address and it comes up with "Destinatin Host Unreachable", nothing else is returning anything positive and most of those only affect the outgoing from here not the incoming from my home. My collegues can still RDP into my server fine from their homes.

My colleagues tracert from home is passing through the Virgin network fine, but struggling as soon as it attempts to penetrate the 02 one?

mynsa · 17 Dec 2009 at 22:43

traceroute relies on icmp, again this is low priority traffic on the net

what I was more interested in is actual packet flow leaving your work and arriving at your home - if it gets that far. What firewall do you use at work and home, does it have capabilities to monitor packet flow?

what happens in your Remote Desktop window when you try to connect, do you just get an error saying timeout or unable to connect etc?

Redgie · 18 Dec 2009 at 12:37

Netgear router firewall both ends, they're not the problem though as my colleague has the same router at home and connects fine.

mynsa · 18 Dec 2009 at 12:44

im not blaming the firewalls / routers, what i am asking to do is to ensure that the traffic is leaving your network and arriving at your home, you can then narrow down the location of the issue.

ignore the icmp stuff, thats low priority traffic, what im interested in is the packet flow of the actual remote desktop packets.

Redgie · 18 Dec 2009 at 15:00

Yeah the guys here at work said the same about ignoring the low priority traffic checks.

How would I go about checking the traffic?