strange ip address w/ router problem

[ne0-reloaded]

I have a wierd problem that im trying to figure out. When i check whatismyip.com with my pc plugged directly into my modem, i get one ip address. when i check when its connected to my wireless router, i get another ip address. the ip address when plugged into my router is wrong because when i try to remote in from somewhere, the only time i can connect is when i use the ip address when give by my cable modem. im using noip.coms dynamic update software to keep my ip addy registered to one of their free sub domains.

my router is a WRT54G v4.0. any help would be appreciated

thanks!

 

[jpmkm]

It's entirely possible to get different IP addresses with the computer and the router(since they have different mac addresses). However, when you check your IP address with a site like whatismyip.com, that is actually the IP address that is visible to the outside world. That site isn't lying to you(unless you happen to be bouncing through a proxy or something, which it doesn't sound like you are). Log into your router and see what address it says it is getting from your ISP. Are you connecting to your router wired or wirelessly?

 

[Malk-a-mite]

Best guess - since I have no idea what level of experience you have I'm going with the simplest explanation for what you are seeing.

I have a wierd problem that im trying to figure out. When i check whatismyip.com with my pc plugged directly into my modem, i get one ip address.

That would be your Public IP address given to you by the cable or dsl modem.

when i check when its connected to my wireless router, i get another ip address. the ip address

That would be a private (non-routable) IP address given to you by your router. The router is assigned the Public IP address by the cable or dsl modem and then in turn assigns your PC (and any other devices you have plugged into it) an different IP address. With the Linksys the IP range will normally be in the 192.168.1.0 range.

the ip address when plugged into my router is wrong because when i try to remote in from somewhere, the only time i can connect is when i use the ip address when give by my cable modem.

As I mentioned above it's a private, non-routeable address. Meaning that routers won't pass connections with that IP address as the destination on to other routers. How you get around this problem is you tell your Linksys router to forward any outside connections to your Public IP to the Private IP on your computer. Normally you pick a few types of connections that you will allow through instead of opening up everything.

 

[YeOldeStonecat]

I agree with M-a-m...it sounds like he's confusing the LAN side (protected inside of the router), with the "wild side"...the IP address the router obtains on the WAN interface.

ne0...that's part of how NAT works, which is what common broadband routers use for 1) Sharing the internet, and 2)...to provide the basic hardware firewall.

 

[kumquat]

That would be a private (non-routable) IP address given to you by your router.

I doubt it. He's using a web-based IP reporting tool, which means that he's seeing two different public addresses.

The reason is that to the server that hands out IP addresses at the ISP, your computer and the wireless router are two completely different machines with different MAC addresses, so they get different IP's.

 

[rodsfree]

I doubt it. He's using a web-based IP reporting tool, which means that he's seeing two different public addresses.

The reason is that to the server that hands out IP addresses at the ISP, your computer and the wireless router are two completely different machines with different MAC addresses, so they get different IP's.

You forget that the ISP can't see anything behind a router like the linksys - it has a built in hardware firewall. Therefore, the ISP can't issue an address directly to the computer.
The DMZ in a linksys router is even NATed....not bridged so the router would still issue an un-routable private IP in the 192.168.1.XX range to the DMZ'd computer.

 

[kumquat]

You forget that the ISP can't see anything behind a router like the linksys - it has a built in hardware firewall. Therefore, the ISP can't issue an address directly to the computer.
The DMZ in a linksys router is even NATed....not bridged so the router would still issue an un-routable private IP in the 192.168.1.XX range to the DMZ'd computer.

I'm not sure what you're getting at, but I can see where the hangup is here. NAT is for all intents and purposes irrelevant to the conversation because the web-based IP reporting tool can only report public addresses to you.

Visit whatismyip.com and it tells you what public address your traffic is coming from. This is totally independent of any NATing that exists.

When he visits that site with the router in place, he gets one public IP. When he visits without the router in place, he gets another public IP.

The reason is that the DHCP server at the ISP is handing out different IP addresses based on the different MAC addresses of the connecting hardware. In one instance, the router's MAC address is requesting an IP, and in the other instance, the PC's NIC is requesting the IP. Hence, the DHCP server gives out different IP's because it's giving them to two different computers.

 

[YeOldeStonecat]

Ahh...I re-read his initial post, I misread it the first time...I had thought he was referring to the IP of his wireless NIC.

ne0...what software are you trying to connect with? Yes you probably have a different public IP when you connect with the two different IPs..and your dynamic DNS updater probably didn't "update" yet with the latest IP address. And...depending upon what remote software you're using, you may or may not have to open/forward the ports in the NAT firewall.

 

[rodsfree]

Me too.....
Missed it.
I thought he was behind the router all the time.

ne0 - What's happening is you've got a cheap cable modem. It is just working in bridged ethernet mode. That means it doesn't even show up in the network, just like the cable doesn't.
The IP differences are due to what kumquat said(Good Catch ). It's because you've got different MAC addresses for the 2 different peices of hardware. You've got to clone your PC's MAC address onto your router. That way the Cable company will think that you've just got your PC connected and nothing else.

Your router's manual isHERE

Go to page 38 and do this.

The Setup Tab - MAC Address Clone
A MAC address is a 12-digit code assigned to a unique piece of hardware for identification. Some ISPs will require you to register a MAC address in order to access the Internet. If you do not wish to re-register the MAC address with your ISP, you may assign the MAC address you have currently registered with your ISP to the Router
with the MAC Address Clone feature.

Enable/Disable. To have the MAC Address cloned, click the radio button beside Enable.

User Defined Entry. Enter the MAC Address registered with your ISP here.

Clone Your PC’s MAC Address. Clicking this button will clone the MAC address.

Change these settings as described here and click the Save Settings button to apply your changes or Cancel Changes to cancel your changes.

Use ipconfig /all on your PC if you want to type in the MAC address or just hit the clone your PC button and the router will get it for you.

This should solve your problem.

 

[ne0-reloaded]

Sorry it took so long to get back, a long day at work. ill try to answer all the Qs that were posted:

It's entirely possible to get different IP addresses with the computer and the router(since they have different mac addresses). However, when you check your IP address with a site like whatismyip.com, that is actually the IP address that is visible to the outside world. That site isn't lying to you(unless you happen to be bouncing through a proxy or something, which it doesn't sound like you are). Log into your router and see what address it says it is getting from your ISP. Are you connecting to your router wired or wirelessly?

the im getting 2 different internet routable address when i check the site. when i log into the router i get one address, and when im connected directly to the modem i get another both are class a address 65.x.x.x, neither are your local 10.x.x.x. or 192.168.x.x addresses. ur right, im not using a poxy, just going through my router/firewall. this happened a while back when i was on dsl. i tried to rdp into whtat i thought was my address, and i got a terminal server for GE. shit was kinda wierd

Best guess - since I have no idea what level of experience you have I'm going with the simplest explanation for what you are seeing.

That would be your Public IP address given to you by the cable or dsl modem.

That would be a private (non-routable) IP address given to you by your router. The router is assigned the Public IP address by the cable or dsl modem and then in turn assigns your PC (and any other devices you have plugged into it) an different IP address. With the Linksys the IP range will normally be in the 192.168.1.0 range.

As I mentioned above it's a private, non-routeable address. Meaning that routers won't pass connections with that IP address as the destination on to other routers. How you get around this problem is you tell your Linksys router to forward any outside connections to your Public IP to the Private IP on your computer. Normally you pick a few types of connections that you will allow through instead of opening up everything.

check the above post. both addresses are routable addreses, both are class A.

I agree with M-a-m...it sounds like he's confusing the LAN side (protected inside of the router), with the "wild side"...the IP address the router obtains on the WAN interface.

ne0...that's part of how NAT works, which is what common broadband routers use for 1) Sharing the internet, and 2)...to provide the basic hardware firewall.

its not NAT, it not tranlating my internal 192 network to a class a network. im getting 2 totally different ip addresses from the site depending on how im connected. the "REAL" address is the one that shows up when im connected directly to the modem. i cant get to my internal network from work using either the no-ip domain name or the ip addy.

Ahh...I re-read his initial post, I misread it the first time...I had thought he was referring to the IP of his wireless NIC.

ne0...what software are you trying to connect with? Yes you probably have a different public IP when you connect with the two different IPs..and your dynamic DNS updater probably didn't "update" yet with the latest IP address. And...depending upon what remote software you're using, you may or may not have to open/forward the ports in the NAT firewall.

Im just trying to get to my ftp site from work. although i am getting 2 different public addresses, the address i recieve when the routers connected seems to be false. i checked again today at work and i cant connect. Im gonna turn off the firewall on the router and the server to see if thatll help, but i doubt it. the dynamic updater updates every 5 minutes. i can manually make it update logging out and logging back into the software. i see the ip addresses change, but still no connectivity. i asked my gf to see if she can remote in and nada (but that was with the firewall on).

Me too.....
Missed it.
I thought he was behind the router all the time.

ne0 - What's happening is you've got a cheap cable modem. It is just working in bridged ethernet mode. That means it doesn't even show up in the network, just like the cable doesn't.
The IP differences are due to what kumquat said(Good Catch ). It's because you've got different MAC addresses for the 2 different peices of hardware. You've got to clone your PC's MAC address onto your router. That way the Cable company will think that you've just got your PC connected and nothing else.

Your router's manual isHERE

Go to page 38 and do this.
Use ipconfig /all on your PC if you want to type in the MAC address or just hit the clone your PC button and the router will get it for you.

This should solve your problem.

Ill give it a try and post back. My heads been out of it lately because of work shit, couldnt even get myself to think so i figured id ask the [H]orde to do the thinkin for me.

Anyways, thanks everyone for all the replies, i really appreciate it!

 

[ne0-reloaded]

rodsfree,

cloning my mac address doesnt resolve the problem. when i clone my pcs address, it drops the dhcp address from my routers wan int. on a side note, wont having 2 exact physical addresses on the same network cause conflicts?

 

[rodsfree]

rodsfree,

cloning my mac address doesnt resolve the problem. when i clone my pcs address, it drops the dhcp address from my routers wan int. on a side note, wont having 2 exact physical addresses on the same network cause conflicts?

The Cloned MAC address is only visible from the external network, so it shouldn't cause any problems internally. The reason it exists is because some ISP's link your IP address to the MAC address of your computer. In theory, this should prevent you from running a small network. It would require you to only use the PC that the ISP had registered. But the more tech savy guys new you could build a router and tell the router what MAC it should use. Linksys and the other mfgs picked up on it and put it into their systems.

As far as the DHCP on the internal side of the router.....
Give the PC a static IP.....like 192.168.1.99
That's a good on because it's in the middle of the 1-254 range and routers have a tendancy to add IP's from the top down or bottom up - depending on the mfg.
Or, better yet, reset the addressable range for the router from 1-254 to 100-254. It's not like you'll ever have 254 PC banging on a linksys....it'd implode!!

Now go www.whatismyip.com and check your IP. It should be the same as when the PC is directly connected to the modem - same MAC addy = same IP (should anyway, unless your provider is real dynamic about IP's.

If it is we're golden, if not we'll have to figure out something else.

Now go to your NAT forwarding table and forward TCP port 21 and UDP port 21 to the static IP that you assigned to your pc. Remember to open these ports in your windows firewall.

Now your ftp server should work.....


Just a question.....Why didn't you just update your new IP with the router at noip?
They've got a "behind a router" step in their setup. And it kinda sounds like you've got the FTP ports open on the PC's firewall, but you don't have them opened and forwarded to the PC in the router. Because it would connect with just the PC and not with the router.

Step 6: Configure your router
If you have a router/firewall in place on the network where your pc/server resides. You will need to make sure that it is configured to allow the appropriate traffic into the destination machine. Please consult your router's manual and look for port forwarding. Common ports to forward are port 80 for web, port 21 for ftp, and port 25 for mail. Only forward the ports that you need to use. To verify that your router is setup correctly, visit www.canyouseeme.org.

Good luck.
Rodney

 

[ne0-reloaded]

As far as the DHCP on the internal side of the router.....
Give the PC a static IP.....like 192.168.1.99
That's a good on because it's in the middle of the 1-254 range and routers have a tendancy to add IP's from the top down or bottom up - depending on the mfg.
Or, better yet, reset the addressable range for the router from 1-254 to 100-254. It's not like you'll ever have 254 PC banging on a linksys....it'd implode!!

Now go www.whatismyip.com and check your IP. It should be the same as when the PC is directly connected to the modem - same MAC addy = same IP (should anyway, unless your provider is real dynamic about IP's.

If it is we're golden, if not we'll have to figure out something else.

Now go to your NAT forwarding table and forward TCP port 21 and UDP port 21 to the static IP that you assigned to your pc. Remember to open these ports in your windows firewall.

Now your ftp server should work.....


Just a question.....Why didn't you just update your new IP with the router at noip?
They've got a "behind a router" step in their setup. And it kinda sounds like you've got the FTP ports open on the PC's firewall, but you don't have them opened and forwarded to the PC in the router. Because it would connect with just the PC and not with the router.

Good luck.
Rodney

I disabled the firewall on the router and on all the nics. i also disable internet protection on all my antivirus apps, to see if i can get any connectivity, and i couldnt. dhcp is disabled on my router; its running on my 2003 domain controller. im not sure what you mean by updating my new ip with the router at noip. i looked through the dynamic update client and the site, and i didnt see anything resembling what youve mentioned. i tried cloning the mac address again, and when i do, it loses an address like it did yesterday. i tried using the dhcp on my router as a last ditch attempt and of course it didnt work either.

any other advice?

 

[rodsfree]

I disabled the firewall on the router and on all the nics. i also disable internet protection on all my antivirus apps, to see if i can get any connectivity, and i couldnt. dhcp is disabled on my router; its running on my 2003 domain controller. im not sure what you mean by updating my new ip with the router at noip. i looked through the dynamic update client and the site, and i didnt see anything resembling what youve mentioned. i tried cloning the mac address again, and when i do, it loses an address like it did yesterday. i tried using the dhcp on my router as a last ditch attempt and of course it didnt work either.

any other advice?

Let me guess.

You are not connecting THRU the domain controller to get to the internet.

A standard Small Office setup with a wireless router would be.....
Cable/DSL modem(in Bridged Mode) to router (which handles all DHCP, DNS Forwarding, Hardware FIrewall, Wireless Connections, etc) to workgroup computers (not Domain)

A more complex setup would have a domain controller and would be recommended for like 30+ computers. It would also need a much faster internet connection.
It would be Cable/DSL Modem(in Bridged Mode) to Domain Controller(which acts as the Router for the network and handles DHCP, DNS, Firewall, et. al.)(this machine MUST have 3 ethernet connections, 1 to modem, 1 to wireless access point or wireless router on a seperate sub net, 1 to network switch). All the network traffic will pass through this machine. And your ftp, http, and other servers would reside on this machine.

After that you're going to have to have dedicated Computers as routers or Cisco routers and seperated Domain Controllers and Servers. CSU/DSU's and 1 or more T-1 lines.

At this point, I'd recommend paying the extra $15.00 a month for a static IP. (That's what my ISP charges, I get 1 for free and $15 for each additional Static IP).
Then set your Domain Controller up to run it the right way.

That would solve your problems.

 

[ne0-reloaded]

Im not connecting through the DC youre right, but im not running a small business either, just messing around with shit on my free time. before i only had my laptop and desktop connected to the wireless router, and still had the same problem. i dont see myself paying an extra $15 a month just so i can get to my mp3s from work. anyways thanks for ur help

 

[ne1wantaride]

After scanning this post.... Do you have port forwarding on your router on? It needs to port forward your ports you need to your internal IP address. ie. 192.168.1.2 or something like that. You should be getting two different ip's because you have two different mac addresses and when you disconnect the cable modem from the router and connect it to your computer your ip is dynamic, hence forth it changes. Check the IP from the router. The router should have a screen to tell you what your ip is. Does that IP match what the internet service is telling you? If is does and you cannot connect to your computer it's a port forwarding issue