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Are any IP address links valid in posts?
I found a question that mentioned a site, with an address that showed up as plain text. I tried to link it, but the edit didn't go through because one can't link numeric addresses. Why is this?
Stack Overflow wants you to only link to public web addresses, accessible to anyone, and with a certain degree of long-evity.
A numerical address is a strong indicator the link is neither meant to be public or will be around (with the same content) for any length of time.
Also, it may be possible to evade some of the black-listed websites with numeric addresses (such as lmgtfy.com and friends), and we wouldn't want that.
