Ha-ha, fail. Extention shows IP of my local proxy-server in my case. Browser using proxy connection in enterprise domain.

Works, gets access denied only on addons.mozilla.org

Simple and reliable. Works great!

Does not work on my system: In the column where the ip should appear, there it says only "access denied".
IPvFox instead works perfectly and does exactly the same.

My system is a windows 10 Home with heavily restricted user rights and a whitelisting firewall (instead of the default blacklisting). Maybe some of those security measures hinder IPvFoo while do no harm to IPvFox. It would be interesting to learn what exactly is it that IPvFoo wants to do violating those security measures.

it s verry good for information

Thanks ! This is exactly what I was looking for !

Thank you says it all. :)

I cannot overstate how happy we are to have found this extremely useful utility. Thank you for building this!

For those wanting to see to which IPv4/IPv6 addresses the website is connections this is a great add-on.

Being very interested in the IPv6 adoption, I like to see if a page is really using IPv6, IPv4, or a mixture.

This extension shows if IPv4 or IPv6 is used just by looking at the extension icon: the big number is for the server on the address bar, the small number(s) showing if components of the page were served by IPv4 and/or IPv6 servers. (Some IPv6 pages are driven by components on IPv4-only servers. For example, my credit union has a dual-stack main page, but all its online banking is IPv4-only.)

Click on the IPvFoo icon, and every server is listed, and whether it is secured, whether it's cached, and (usually) the IP address. It's all presented in a very nice table.

The only shortcoming I have seen so far is if some components are cached from activity on another tab so a server isn't accessed by the current tab, the IP address of that server wont' show; but a "refresh ignoring the cache" (Ctrl+F5) fixes that, at least for the current page. (I hope a future version would resolve the IP address in this situation, but I think it's 5-star-worthy even as it is today.)

Overall, I am very glad to see IPvFoo here for Firefox 57+. I first came across it when I was using Chrome and in Chrome I have absolutely no reservations in recommending IPvFoo!