On Mon, May 22, 2023 at 08:41:13AM +0100, Tim Woodall wrote: > On Sun, 21 May 2023, Timothy M Butterworth wrote: > > > The only address that should have a netmask of 255.255.255.255 is the > > Loopback interface. > > > > I don't much use ipv4 any more if I can avoid it but isn't it normal for > point-to-point links to have a netmask of 255.255.255.255?
Right -- this one designates an isolated host address: "the computer is the
network" [1]. I think it's rather used to designate host routes or single
hosts in firewall rules. For point-to-point links I think a /23, i.e.
255.255.255.254 seems more appropriate.
> It definitely can be, maybe not so common as I assumed.
>
> loopback is a /8
Most definitely:
tomas@trotzki:~$ ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group
default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
(I actually make use if it when I want to test web pages locally and want
a host IP different to localhost).
Cheers
--
t
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