ID IP Address of Cable Modem Hooked to Linksys Router

Not me, but you could install wget to fetch the web server page and use some script language, like perl, to parse the page and display the contents you desire. Both are free for download for Windoze. I run Mandriva Linux myself.

I use wget to pull my cable modem page and parse the signal values with perl to warn me when cable modem values are outside my normal values.

I also wrote a bash script to parse the DHCP values to warn me of short lease times which usually happens when they are doing network maintence work and tell me when my gateway/DNS servers change value.

There are many web sites that will tell you exactly what IP address you're coming from.

Google is your friend.

Does the router support SNMP?

You can easily do it in Perl as well as the wget suggestion. If you have Perl, I can give you a script to retrieve the web pages (we'll need to modify it for your particular brand/model).

WG (my config page starts with) :

Config Page Modem IP 10.22.xx.xx

So it's easy to strip the IP address from the page. If you have a website out there with CGI, you can easily return any info you like from the connection made using your browser/Perl/wget.

Wow..how insightful. Nice to see that you really took the time to grasp the essence of my post. Google? Sheesh, never in a million years would I have thought of that. You go girl!

On my Linksys, I can drill right to the page that shows the status (i.e.

10.10.10.1/status.htm). The status page does show the cable modem's IP address. However, that requires a username and password which is cumbersome, esp. if I don't check the box to save the password. Thanks for your idea. I will try to script something and see what I can come up with..I was really hoping for a program that was already in circulation that would do this. Thanks!

RD

"RD" wrote in news:pvidnQea1J4-xYXYnZ2dnUVZ snipped-for-privacy@insightbb.com:

I use IP2 from

displays the local IP of the computer it is run on, and at the same time queries one of a list of servers that returns the WAN IP of the router. It's only one of several small utilities from that page that I use. Check out Hash 1.03 while you're there. The programs are free and are ad-free also. No malware.

You download the zip file and unzip it to your hd. You must create a shortcut for it and place it where you can click on it. There's no install program as such.

I thought it was a prety good response. There are sites that will just echo the IP you are calling from (which would end up being your modem's IP). Here's just one:

So does mine - it's still easy to do in Perl (of course you will need to put the router password in the script). If the script was already in circulation, how would it be able to know each router's web page output ?

The IP echoing sites (as perviously mentioned and ignored) easily get around that if that's all you need.

That is exactly what I was looking for. You are da' man! Thanks!!!

RD

Actually, I thought Elmo's suggestion was the simpler one to implement. Your initial question implies that you want to know your public (WAN) IP address. You can get that from the router, as you know, but doing so requires a login/password. You can also do it via any of a handful of Internet web sites, and in that case no login is required. It's your choice, but the "no login" option seems a bit easier in case you've never scripted anything before. If you do have that experience or are willing to learn a bit, then either way will work equally well.

I get mine via a simple snmp command:

$ snmp_request 192.168.2.1 public getnext 1.3.6.1.2.1.4.20.1.1

1.3.6.1.2.1.4.20.1.1.ww.xx.xx.zz = ww.xx.yy.zz

Many of us, (me anyway), don't run SNMP at home. I get enough of that crap at work. :)

Sweet. Nice find.

No. That's the IP address assigned to the CPE connected to the modem. In my case, it's my router's IP, which can also be found in the headers of this post.

Because the cablemodem is just a bridge, upstream servers don't need to be aware of it's IP address, and they do not report it, either. Someone else mentioned a tool called IP2. This also does not report the modem's IP address, but reports the IP address of the CPE connected to the modem.

If you have a typical computer -> router -> cablemodem -> Internet configuration, there are a number of IP addresses involved.

-Your computer will likely have a 192.168.x.x number assigned by the router.

-Your router will have a 192.168.x.x address that it's known by to the computers on your LAN.

-Your router, being the CPE, will have an IP address assigned by the cable network's DHCP server. To the outside world, this is "your IP address".

-The cablemodem has a 192.168.x.x address that can be accessed only from the CPE side of the cablemodem. This is the address that you use to access the internal webserver that gives you status and diagnostic information about the modem.

-The cablemodem also has a 10.x.x.x address that can be accessed from the cable network. This address is usually only used for troubleshooting and some administrative purposes that are done by the network admins using TCP/IP.

If you are looking at a public range IP address that is associated with you, it is your CPE's IP address, not the cablemodem's IP address. The cablemodem does not have a public range IP address. It has a class C private address on the CPE side, and a class A private range address on the network side. And you're not going to be able to get that address from upstream servers, as they don't care about the IP address of a bridge on the way to the CPE.

The question was how to get the address. Whether or not you think SNMP is crap is irrelevant. SNMP has been incorporated into most networking equipment -- crap or otherwise -- and is a useful way to obtain statis- tics and information from the device.

Humor impaired, eh? I know exactly what SNMP is, how to use it, and what I can do with it. Since I have to deal with it at work and it's generally unpleasant for me, mostly because of who I have to work with to get anything done, I choose not to work with it at home. Better?

I still say many of us don't mess with SNMP at home. Maybe we should just leave it at that.

Not to mention that snmp_request is not all that readily available for a Windoze platform for one - and not all routers/modems respond equally to SNMP. It would in the end be more work just trying to get the necessary downloads done before you could get started.