Remote Administration - Help please

**glapalom** · 02-19-2003, 07:10 PM

I am trying to understand how to connect from a home PC to a server on my work network. Here is the scenario. Previous admin. set this up and I have no way to contact him so here goes...

MS Exchange on server A: (internal IP address only)
Firewall on Server B: eth0 - internal IP, eth1 - external IP
SonicWall router for Gateway

I want to reach server A from home. Admin. installed 'RA Manager' so he could take control of desktop. I want to do the same.

RA Manager wants the gateway IP, and the target or 'slave' IP. It also wants the port to communicate on.

I know the gateway IP, but I am having trouble with the slave IP and the port.

MY QUESTION - What typical files do I look into on the RH Firewall Server in order to see what IP is available to the outside world and what port is available also?

Here is what I assume... There is an IP address defined on the linux box that when used is actually redirected to an internal IP. I just don't know where to look to find that out.

Any help is much appreciated.
G

**Compunuts** · 02-21-2003, 06:06 AM

[quote author=glapalom link=board=4;threadid=6408;start=0#60421 date=1045685442]
MY QUESTION - What typical files do I look into on the RH Firewall Server in order to see what IP is available to the outside world and what port is available also?
[/quote]
If you do ifconfig as root or /sbin/ifconfig as regular user, it should show you what IP address are assigned to specific net connection.
If you check /etc/services file, it should show you the general listing of what port are assigned to what services BUT it will not show you what port are being opened at that moment. For that, you will have to use other tools such as nmap to find what ports are open in that server. Do a query on nmap in google and it should get you started.

Here is what I assume... There is an IP address defined on the linux box that when used is actually redirected to an internal IP. I just don't know where to look to find that out.

It depends on the set up but mostly done via NATting. Network Address Translation is mostly used in Gateway servers setup.

**tolstoy** · 02-21-2003, 06:48 PM

If any of your boxes are using NAT, then you will have to set up port redirection on your Linux firewall, and possibly on your Sonic Wall.

Doing an ifconfig will show you all the ipaddresses assigned to your Redhat Firewall. What you need to do, if this box is in fact using NAT, is set up port redirection. Do a google search to find out what port you need to open for your RA client to reach the RA server. If this in Win2k we are talking of here (on the Exchanmge server, that is) then do not use the Remote Assistance tool built into XP and instead make a terminal server connection with XPs built-in RDP client (its in the Start menu somewhere). If you are in fact using Win2k's terminal server than the port you want is tcp port 3389. I'm pretty sure that you cannot use Remote Assistance to remotely administer as Win2k server. If you find this to be true, you will need to make a TS (terminal server) connection to it. This, of course, assumes that Terminal Server is in fact installed on the Exchange box and that it is running in Remote Administration mode.

Now you will now need to configure your firewall in such a way that it intercepts packets bound for tcp port 3389 and forwards them to your exchange server. And, if you are in fact also firewalling things on your Sonic box, you will need configure that too to allow RDP traffic to and from your network.

So, to make a long story short:

1) User Terminal Server Client, not RA
2) Set up yout NAT box and all your firewalls to pass, or redirect RDP traffic (tcp port 3389)
3) Point your Terminal Server client at the external "live" ip address of what ever box is doing NAT.

Before any of us can help further, I think we need to know the following:

1) Is the Sonic Wall also firewalling, or is it simply routing packets?
2) Which firewalls/gateways are doing NAT translation
3) How are you configuring your firewall on the RH box? Scripting iptables by hand or using some other tool?

I hope this helps.

What you want to do is entirely possible. I have techs who TS into some of my servers through my firewall to remotely administer them. However, be forwarned, I would not open up internal servers to external connections unless you know exactly how to configure your firewalls to restrict access to only those remote clients you specify.

Is this all too confusing?

**glapalom** · 02-23-2003, 02:26 AM

Thanks to both of you. I will try to find out the answers to your questions on Monday (time permitting). See, I don't know whether the previous guy setup iptables or ipchains.

I do have to make one correction. It's a Netopia router not a Sonicwall. Thanks.

G