Re: Address 127.0.1.1
On Fri, May 24, 2024 at 05:22:13PM +0100, Joe wrote:
> Long ago, lo used to be just 127.0.0.1, which is what most people would
> try to ping to check localhost, and what appeared in /etc/hosts. There
> is some subtle reason, which I used to know but have now long forgotten,
> why Debian started using 127.0.1.1 in /etc/hosts instead.
It's not "instead". It's "in addition".
hobbit:~$ head -n2 /etc/hosts
127.0.0.1 localhost
127.0.1.1 hobbit.wooledge.org hobbit
The first line is traditional. Exactly what it looks like.
The second line ensures that my hostname will always resolve to a
working IP address. Lots of programs need that. Some of the most
common reasons back in the old days were X clients that had been
told to use "myhostname:0" as their $DISPLAY. If "myhostname" didn't
resolve to a working IP address (one which could contact the X server),
then X client programs wouldn't work.
A lot has changed since then, but the basic principle remains the same.
Some programs are going to expect to be able to open a network connection
to whatever IP address the system's hostname resolves to. 127.0.1.1
serves that purpose, without stepping on 127.0.0.1 which has its own
legacy role to fulfill.
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