this post was submitted on 01 Aug 2025
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[–] marine_mustang@sh.itjust.works 17 points 2 days ago (1 children)

C’mon, IPv4 has so many problems. Sure, let’s reserve a whole /8 for a single loopback address, that’s efficient. 🙄

[–] TheFogan@programming.dev 20 points 2 days ago (1 children)

Well of course, how else would you trick script kiddies that figured out when they DDOSed 127.0.0.1 and learned what a loop back was, and get them again in a few weeks with "ok ok my real address is 127.34.21.2"

[–] vrek@programming.dev 4 points 2 days ago (2 children)

Wait... I know 127.0.0.1 but what's the second one?

[–] TheFogan@programming.dev 18 points 2 days ago (1 children)

not sure if you are joking, but any valid IP4 address starting with 127. does the same thing, loopback. 127.0.0.1 is just the standard most people use, you could use 127.127.127.127, or 127.1.1.1 or any random numbers 0 and 254 for the second 2, and 1 and 254 for the last and the effects will be identical.

[–] frezik@lemmy.blahaj.zone 11 points 2 days ago

In fact, it's so standard that there's a bunch of shitty code out there that thinks 127.0.0.1 is the only loopback address.

I'm thinking of a networked Chinese laser cutter that we put on our 10.0.0.0/16 network in the makerspace. It seems to think that 10.0.1.1 and 10.0.2.1 are on different networks. Wouldn't be surprised if it does a similar mistake with loopback addresses.

[–] ramjambamalam@lemmy.ca 5 points 2 days ago* (last edited 2 days ago)

A /8 subnet is basically everything after the first of the four segments, e.g. 127.*.*.*. marine_mustang was saying that loopback (what you think of as only 127.0.0.1) is actually an entire subnet, so any address that starts with 127 will hit the loopback interface. TIL, never thought about it much before.