Recently, I saw icanhazip.com pop up in my pFsense firewall logs. It was immediately blocked but the name piqued my interest, so I did a little digging which revealed an interesting backstory.
It’s owned by Cloudflare:
spoiler
spoiler
…but it hasn’t always been theirs: icanhazip: How a simple IP address tool survived a deluge of users. Pretty interesting, at least to me as I have never encountered it before.
I have it still blocked as nothing I’m doing seems hampered by blocking icanhazip.com’s ip range. Anyone else ever encounter icanhazip.com?
I think I found the source of the icanhazip.com block. From the Github Issues page:
2025-03-27 17:00:02] production.ERROR: Failed to fetch external IP address. [“cURL error 60: SSL: no alternative certificate subject name matches target hostname ‘icanhazip.com’ (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) for https://icanhazip.com/%E2%80%9D]
ETA: Solved
I think I found the source of the icanhazip.com block. From the Github Issues page:
2025-03-27 17:00:02] production.ERROR: Failed to fetch external IP address. [“cURL error 60: SSL: no alternative certificate subject name matches target hostname ‘icanhazip.com’ (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) for https://icanhazip.com/”]
I actually worked with Major back when he initially created icanhazip.com. It’s still my go-to for resolving my public IP for scripts that need it. (IE. hand rolled DNS for my home lab k8s cluster).
Wow! It certainly a small world after all.
I must have been a very early user if only went live in 2009! It’s a great resource that’s always fast and optimally concise.
I didn’t know this backstory though, thanks for sharing.
Lots of people use it, I recommend they try ifconfig.co - cleaner curl output.
Interestingly enough, ifconfig.co shows up too. I knew about ifconfig.co tho. Since the last container I added was SpeedTest Tracker to replace OpenSpeedTest, and that’s about the time icanhazip.com showed up, I am assuming SpeedTest Tracker is using both ifconfig.co and icanhazip.com to determine the
localexternal IP and the closest test servers to it. The request is originating from the LAN. However, I selected my own servers I wanted to use based on my locale, so blocking either hasn’t stopped SpeedTest Tracker from doing it’s tests on an hourly basis.
I use ipecho.net, or ipecho.net/plain if I’m using curl
The thought just struck me that there may be who knows how many of these out in the wild. Little ‘touch stones’ that people use across a global internet.
Thanks for the post, was an interesting read
