UGN Security


Posted by: Lord AwoL

winipcfg? - 02/24/03 02:52 AM

I've been used to using the DOS winipcfg command to bring up my IP address on older Windows versons. I've recently started using XP professional, and this command doesn't work. How can I find out what my IP address is under XP?
Posted by: pergesu

Re: winipcfg? - 02/24/03 02:57 AM

start->run->cmd and type ipconfig
Posted by: mtlhd

Re: winipcfg? - 02/24/03 02:58 AM

Ummm...Does ipconfig work?
Posted by: BackSlash

Re: winipcfg? - 02/24/03 03:09 AM

it worked for me
Posted by: Gremelin

Re: winipcfg? - 02/24/03 03:20 AM

You have to download WinIPCFG. You can actually take winipcfg.exe from an older windows version and drop it into your c:\windows\ directory and run it as usual.
Posted by: unreal

Re: winipcfg? - 02/24/03 07:39 AM

...Or you could do it the easy way and type 'ipconfig' from a command prompt. :x
Posted by: SilentRage

Re: winipcfg? - 02/24/03 03:58 PM !!!

(but yeah, ipconfig in 2k/xp for shore)
Posted by: Scalli0n

Re: winipcfg? - 03/01/03 08:54 PM

use the networking control panel, that's why windows is a GUI.
Posted by: Paragon

Re: winipcfg? - 03/01/03 10:39 PM

Just pointing out, that if you're on a network, you will essentially have two IP addresses, your internal IP on the network, which you need ipconfig to see, or your external one, that people on the internet see. will show the external one.
Posted by: Scalli0n

Re: winipcfg? - 03/02/03 03:11 PM

Continuation of paragons post....

That would be the router that handles your networks traffic's IP (or firewall, etc.) but basically it's the chokepoint IP. Your internal IP means nothing to the outside world, it's standard to ignore traffic to/from those IP sets in realms outside LAN's.
Posted by: pergesu

Re: winipcfg? - 03/02/03 06:38 PM

Alright, well while we're kinda on this... How does a router work then? I've never really understood how when you make a request to a web site, the responses get routed back to your computer. Is there some part of the TCP or IP protocols that account for NAT? How does the router know which computer the packets are supposed to be routed to?
Posted by: SilentRage

Re: winipcfg? - 03/02/03 07:28 PM

Well, the best way I can think of to answer your question is to draw ya a diagram of exactly what happens when you connect to

ok, here's an example where you are connecting to without a router...

'You ask to SYNchronize a connection
you -> TCP SYN packet ->
Source IP:
Target IP:

' ACKnowledges the SYN and says all is go -> TCP SYN/ACK packet -> you
Source IP:
Target IP:

'you acknowledge the SYN/ACK. connection complete
you -> ACK ->
Source IP:
Target IP:

there's the connection sequence. understand? good. Now let's take a look how it differs when a router is thrown into the mix. Now, one thing to keep in mind. When directly connected to hte internet, our Gateway was configured by your ISP. A gateway is where a computer sends all of it's packets that don't belong in the local network (specified under the subnet mask). So if you have an IP of and your subnet mask is then all packets destined for a 192.168.1.x is sent directly to the computer, and everything else is sent to the Gateway. The Gateway is your access to the world. When you have a router configured at, then THAT is your Gateway. THAT is where all packets are sent from your computer that isn't on your local lan. So here's what happens when you send a connection request to

key = router external IP = router lan IP = your IP = IP


'SYN packet sent from you to the router. -> TCP SYN ->

'router caches information in it's routing table that is connecting to

'SYN packet sent from router to -> TCP SYN ->


'SYN/ACK packet sent by to the router -> TCP SYN/ACK ->

'router checks it's routing table and sees that is an IP that is connecting to. To keep track of multiple connections from multiple computers on the LAN to, keep in mind that each connection to requires a unique router local port. So all responses to that port that matches the stored routing information is passed through to the relevent lan computer.

'router sends packet to the lan computer -> TCP SYN/ACK ->


'you send the connection acknowledgement to the router -> TCP ACK ->

'router sends it off to yahoo -> TCP ACK ->
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