ASUS Router Merlin showing two differnt WAN ip address

zillah · Post by **zillah** » Wed Jul 07, 2021 2:09 am

Dear folk

I have got ASUS ROUTER RTAC5300 with Merlin firmware latest version

Before I connected to VPN and thorough the website

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https://whatismyipaddress.com

it was showing public ip address different from the "General" --> "Network Map"

And now when I connected to VPN it is still showing two different public ip addresses please see attached snapshots

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[URL]https://imgur.com/a/lRz7T3A[/URL]

Why is it happening like that ?

Thx

Post by **Philip** » Wed Jul 07, 2021 9:18 am

Hello Zillah, good to see you around

The 103.212.x.x. IP is your actual external public IP address that is seen onto the internet.
The 100.97.x.x IP address is a private address, generally reserved for NAT between internet service providers and subscribers. Any IP between 100.64.0.0 ~ 100.127.255.255 (100.64.0.0/10 prefix) is reserved for carrier-grade NAT.

In other words, your ISP is using NAT to give out more private IPs to their subscribers, and then translates between those private IPs and public IPs seen onto the internet.

You could see your IP on our site here: https://www.speedguide.net/ip/

And the private/reserved IPs are listed here: https://www.speedguide.net/ip/100.99.1.1

I hope this helps.

zillah · Post by **zillah** » Thu Jul 08, 2021 5:59 pm

Hi Philip

Thanks for your help and I have to admit learning a lot from your knowledge

The 103.212.x.x. IP is your actual external public IP address that is seen onto the internet.

Yes no doubt

The 100.97.x.x IP address is a private address, generally reserved for NAT between internet service providers and subscribers. Any IP between 100.64.0.0 ~ 100.127.255.255 (100.64.0.0/10 prefix) is reserved for carrier-grade NAT.

This is something new to me and it makes sense ,,,,,,but now I have got a question

Has this been a practice by ISPs since while ?? As what I had seen in past public ip addresses not the ip 100.x.x.x range ,,,,please see for instance attached snapshot that captured April 28 2019

https://imgur.com/a/BmVROhx

Then the same router it is public ip address changed to 58.17x.7x.12x on May 5 2020 (I didn't take a snapshot I just recorded the value into an Excel sheet)

Other routers unfortunately I didn't record their public ip addresses

Post by **Philip** » Fri Jul 09, 2021 11:44 am

This is usually practiced by smaller ISPs, when they have more customers than the available to them IP pool (version4).

Used to be more common years ago, haven't seen US ISPs do it for a while, as IPv6 becomes more prevalent.

zillah · Post by **zillah** » Fri Jul 09, 2021 7:00 pm

This is usually practiced by smaller ISPs

Differently this is my case now it makes seance
Thx Philip