Troubleshoot Why does my ISP give me 2 totally different ip addresses ?

[ng4ever]

I use to have a 68.xxx.xxx.xxx ip address now it is 98.xxx.xxx.xxx ip address.

It is after I reflashed my router to the Asus default router firmware. I was trying to fix a QOS issue.

The perfectionist in me prefers a 68.xxx.xxx.xxx ip address.

Anyway to get it back ?

 

[imsoadude]

Very likely if they are just handing out dynamic public IPs then it is by chance whether your router holds on to it or not. While you were doing an upgrade the ip would have not been bound and its possible its been assigned to someone else.

 

[Digerati]

The perfectionist in me prefers a 68.xxx.xxx.xxx ip address.

Not sure what being a perfectionist has to do with this. The 68.xxx IP is no better than the 98.xxx IP.

That said, I have to say it is curious (but not harmful) you would get a different first octet. Did your ISP recently merge with another?

 

[grumpy_joe]

Hah, someone else took it (literally).

 

[imsoadude]

Not sure what being a perfectionist has to do with this. The 68.xxx IP is no better than the 98.xxx IP.

That said, I have to say it is curious (but not harmful) you would get a different first octet. Did your ISP recently merge with another?

Doesn't necessarily means they merged could be that they applied or purchases a block of public ip addresses and then later again applied for more. The ISP I work for recently bought public IPs starting with 192.*.*.* and then recently got a block assigned to us from ARIN of 208.*.*.* so in our network people's routers could get either subnet.

 

[ForgottenSeer 58943]

I use to have a 68.xxx.xxx.xxx ip address now it is 98.xxx.xxx.xxx ip address.

It is after I reflashed my router to the Asus default router firmware. I was trying to fix a QOS issue.

The perfectionist in me prefers a 68.xxx.xxx.xxx ip address.

Anyway to get it back ?

You don't have statics so your ISP just drops you in whatever scope has free leases prioritized by the most open scope. You could in theory force the lease time to expire and assign yourself a new IP. Unplug your cable modem from the power, unplug the coax from the cable modem and go to bed. Wake up in the morning and plug everything back in and your lease should have expired and you'll gave a new IP.

In theory, yes there is a way to get the other one back - purchase statics. But for a home user statics would largely be useless.

 

[Digerati]

Doesn't necessarily means they merged

I realize that. That's why it was a question, not a statement of fact.

The ISP I work for recently bought public IPs starting with 192.

You sure? 192.xxx.xxx.xxx is generally reserved for private, not public networks. That's why most routers assign IP address beginning with 192. For example, 192.168.1.0 and 192.168.0.1.

See, What does "192" mean in an IP addresses and What is it?

 

[imsoadude]

I realize that. That's why it was a question, not a statement of fact.

You sure? 192.xxx.xxx.xxx is generally reserved for private, not public networks. That's why most routers assign IP address beginning with 192. For example, 192.168.1.0 and 192.168.0.1.

See, What does "192" mean in an IP addresses and What is it?

192.168.*.* is reserved for private, outside of that is not.

IPv4 Private Address Space and Filtering

 

[Digerati]

Interesting. Thanks.

 

[ForgottenSeer 58943]

Subnetting and networking 101.

192 scope is not reserved for private use, the second octet denotes the private Class C subnet. 10.0-10.255(CA), 172.16-172.32(CB), 192.168-192.168.255(CC). Many people falsley believe that 172 denotes a private subnet. Not correct - 172.15.0.0 would be public, whereas 172.16.0.0 would be private.

Also, most people don't realize this, but you don't have to use private IP spaces defined by IANA. You can vary from it as you wish. You can use any range you want on your internal LAN including routable internet address ranges. The only problem it could manifest in is if a public website/server coincides with that scope there would be a routing loop. Also there is a chance your internal could be exposed publicly if your security isn't tight. I've worked on corporate networks with a DHCP pool of 1,200 clients running on 169 public ranges. So it happens.

 

[Digerati]

Also, most people don't realize this, but you don't have to use private IP spaces defined by IANA. You can vary from it as you wish.

I knew that. That's why I said above, "generally reserved" and "most routers". My thought being it was a "recommended" standard that "most" router makers complied with. I was not suggesting it was a required standard.

I also knew it was 192.168.x.x but sadly, I suffer from CGCF and had one of my occasional flare ups - I simply forgot and failed to verify my facts before posting. Sorry.

(CGCF - chronic geriatric cranial flatulence)