Modem IP different from Router IP

Erah

Occasional Visitor
Hello all,

My WAN IP (from modem) is different from my WAN IP (on router).

When modem is in bridge mode, my Public IP (IPv4) is changed and shows incorrect location.

When modem is not in bridge mode, my Public IP (IPv4) is different but shows correct location.

How can I get both to match that of the modem?

Thanks.
 

Tech9

Part of the Furniture
Try cloning the modem's MAC address.

In WAN, Internet Connection:

1670032653445.png
 

Tech9

Part of the Furniture
Well... get the modem's MAC address, of course. Copy and paste there, disconnect the WAN cable, hit Apply at the bottom of the page, power down your router. Switch the modem/router in modem bridge mode from its GUI, wait for it to reboot, connect the WAN cable, power your Asus router back on.
 

sfx2000

Part of the Furniture
My WAN IP (from modem) is different from my WAN IP (on router).

are you on 5g fixed wireless access?

Your WAN IP on the router might be a private/NAT IP address in IPv4 space...
 

Erah

Occasional Visitor
Well... get the modem's MAC address, of course. Copy and paste there, disconnect the WAN cable, hit Apply at the bottom of the page, power down your router. Switch the modem/router in modem bridge mode from its GUI, wait for it to reboot, connect the WAN cable, power your Asus router back on.

Okay, trying to see which MAC address to use now. There's CM MAC, WAN MAC, & eMTA MAC.
 

Tech9

Part of the Furniture
WAN MAC Use CM MAC, sorry. Must be printed on the modem's label as well.

Also, read what @sfx2000 is saying above. It's quite possible you get CG-NAT WAN IP address.
 
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Tech9

Part of the Furniture
Rogers Cable provides 2x public IPv4 + 2x IPv6 addresses to modem/router in bridge mode. You have to use LAN1 or LAN2 for IPv4 address.
 

Erah

Occasional Visitor
WAN MAC Use CM MAC, sorry. Must be printed on the modem's label as well.

Also, read what @sfx2000 is saying above. It's quite possible you get CG-NAT WAN IP address.

Okay, going to try CM MAC now.

Not sure if Rogers is providing me with CG-NAT tho.
 

Tech9

Part of the Furniture
I tested this and although the WAN IP is different indeed it has no effect on Internet experience. I'm using TekSavvy on Rogers Cable and the location change is in the same city. This is not a concern. There is nothing to fix in my case. CG-NAT is a private IP range @sfx2000 is talking about.
 
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Erah

Occasional Visitor
I did all the steps you listed, now it’s showing up as “Your ISP’s DHCP does not function properly.”
 
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Tech9

Part of the Furniture
Remove the cloned MAC and reboot the router. What so much different location you are getting?
 

Tech9

Part of the Furniture
Interesting. I have to experiment with MAC cloning because I'm not sure now what it means in Asuswrt. Some ISP's detect the first device connected after their modem and don't allow routers. This is perhaps why Asuswrt clones the computer's MAC with an idea to represent your Asus router as known to the ISP client. This is different than what I was expecting to happen. I need to invite someone like @ColinTaylor for an opinion on this case.
 

Erah

Occasional Visitor
Makes sense. It’s not that big of a deal, but still bothers me a bit as a competitive gamer. My geolocation within the game itself is always set to Montreal, QC - which adversely affects my ping & the servers which the game routes me to. Just wanted everything to mesh perfectly but it is what it is.
 

RMerlin

Asuswrt-Merlin dev
Precise geolocation by IP will never be fully accurate and reliable. A Toronto-based ISP gets allocated IP ranges. How they allocate these IPs between their customers in different cities will vary and may not be city-specific. Databases can also get out of date, and contain no longer accurate info.
 

Tech9

Part of the Furniture
Some features in home routers have similar names to features in business equipment, but adapted to home use. Like DMZ in home routers. I was expecting something different here. Is there a solution to this problem using an Asus router @RMerlin? I don't know why the ISP is not accepting the cloned modem MAC. I can ask tomorrow what is Rogers expecting to see, but you may have experience already.

Sorry @Erah for wasting your time. :oops:
 

RMerlin

Asuswrt-Merlin dev
I don't know why the ISP is not accepting the cloned modem MAC. I can ask tomorrow what is Rogers expecting to see, but you may have experience already.
Not sure which specific problem you are referring to, but if you mean the ISP didn't allocate you a new lease after cloning the MAC, that's because cable providers will keep in memory the last MAC that requested a DHCP lease, and will refuse to allocate a new lease to a new MAC until you get that previous MAC to be flushed from their memory. With Vidéotron, that requires unplugging the power from the modem for at least 5 minutes. Rogers is probably similar (but the required downtime may possibly be different).

The MAC has to be from the DHCP client, that`s why the clone is by default from the client PC, and not the modem. The modem's MAC is only used for authenticating with the CMS, not for obtaining the DHCP lease.
 

drinkingbird

Very Senior Member
Hello all,

My WAN IP (from modem) is different from my WAN IP (on router).

When modem is in bridge mode, my Public IP (IPv4) is changed and shows incorrect location.

When modem is not in bridge mode, my Public IP (IPv4) is different but shows correct location.

How can I get both to match that of the modem?

Thanks.

After going through all the hassle of hacking something together, in a few weeks or months you'll get a new IP that will be from another city (and province in your case).

What is the issue with it? If you want advertisements and websites to know your precise location, then turn on location in windows and put in your city, and allow it in your web browser.

Geo IP DB is not reliable. I've even seen people get ones from another country when a global ISP reallocates IPs or buys some from an ISP in another country. That really causes havoc as a lot of banking sites etc will not let you connect. That seems rare nowadays, I think they realize they really must get GEO IP updated when they do that or their customers will start calling.

If it is really important to you, you don't have to clone the modem MAC (that probably won't work since the router is behind the modem, not in front of it). Turn off your modem, clone the MAC of anything behind the router, turn on the modem, see what IP you get. If you don't like that one, repeat the process with some other device behind the router. Or wait a few days and try it again. It is luck of the draw what pool you're pulling from. It is possible that for some reason they have a pool for bridge users and a pool for router users, seems unlikely though.
 

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