Public IP shows strange characters and Facebook registers logged-in session to Mount Laurel, NJ

I'm encountering some IP strangeness today and hoping to find an explanation.

In short, I'm based in Seattle, WA with my ISP being Comcast. While browsing Facebook's account settings, I noticed that my active session was located to Mount Laurel, NJ.

At that point I ran a search in Google for 'my public IP', which returned an interesting result: a string of characters in the following format:

2601:8:b000:xxx:xxxx:xxxx:xxxx:xxxx

Normally, a search for my IP returns something like:

67.xxx.xx.xxx

A phone call to Comcast got me nowhere, but using Comcast's phone-menu debugging tools, I was able to send a 'refresh signal' to my modem. After that, the search for 'my public IP' yielded the expected result... for about 5 minutes, and then it returned to the new string of characters.

Does anyone know of an explanation for this?

Stuart Kershaw

Posted 2013-11-08T20:53:49.270

Reputation: 123

3That looks like an IPv6 address... – nhinkle – 2013-11-08T20:54:52.213

Answers

If you click the "Learn More" link that shows up when you Google for your IP, it explains what you're seeing:

IP addresses are sequences of numbers that are usually displayed in readable notations, such as 172.16.254.1 (for IPv4) and 2001:db8:0:1234:0:567:8:1 (for IPv6).

Comcast has both IPv6 and IPv4 enabled for many of their regions.

For more info on that, you can visit their IPv6 Information Center: http://www.comcast6.net/

Most recent entry there:

Published on Friday, September 20, 2013
Residential native dual stack has been launched to Comcast customers across Washington state!

Ƭᴇcʜιᴇ007

Posted 2013-11-08T20:53:49.270

Reputation: 103 763

Wow, the first post on that page is very relevant. It's posted Sept. 20 and mentions the launch of IPv6 across WA state. This accounts for my not seeing the alternate IP in the past. Thanks for the link. – Stuart Kershaw – 2013-11-08T21:14:18.390

That is your IPv6 address. Your 67. number is your IPv4 address.

From a command prompt, type:

ipconfig /all

and you will see both

Keltari

Posted 2013-11-08T20:53:49.270

Reputation: 57 019

2If they have a router, then they will see a different set of IP addresses. – daxlerod – 2013-11-08T20:58:02.470

The set of IPv6 adresses that start with 2601:: are registered to Comcast in Mt. Laurel, NJ. http://whois.arin.net/rest/net/NET6-2601-1/pft

– daxlerod – 2013-11-08T20:59:01.773

Interesting, I've not seen the IPv6 address displayed before, and I've certainly not had my location traced to Mount Laurel, NJ during an active session. Would there be any reason for the IPv6 address to begin returning in searches and on FB? *Note that this occurs from any device on the network. – Stuart Kershaw – 2013-11-08T20:59:51.143

Note that Mt. Laurel is in Burlington county NJ, approx 15 mins outside of Philadelphia, Comcast corp headquarters. They have a lot of equipment in Camden and Burlington counties. – horatio – 2013-11-08T21:16:15.627

1@daxelrod: The IPv6 address should be the same whether they have a router or not. IPv4 addresses are normally those of the router (NAT device). If IPv6 privacy is enabled, the IPv6 address will change over time. – BillThor – 2013-11-08T21:42:31.360