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Re: netmask question

From <tomas@tuxteam.de>
Newsgroups linux.debian.user
Subject Re: netmask question
Date 2023-05-22 10:10 +0200
Message-ID <Gy8M9-aCXh-1@gated-at.bofh.it> (permalink)
References <Gy3Mt-azy9-1@gated-at.bofh.it> <Gy3W9-azB9-1@gated-at.bofh.it> <Gy8sN-aCBa-1@gated-at.bofh.it>
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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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Thread

netmask question coreyh@free.fr - 2023-05-22 04:50 +0200
  Re: netmask question Timothy M Butterworth <timothy.m.butterworth@gmail.com> - 2023-05-22 05:00 +0200
    Re: netmask question Tim Woodall <debianuser@woodall.me.uk> - 2023-05-22 09:50 +0200
      Re: netmask question <tomas@tuxteam.de> - 2023-05-22 10:10 +0200
      Re: netmask question coreyh@free.fr - 2023-05-22 11:00 +0200
        Re: netmask question Tim Woodall <debianuser@woodall.me.uk> - 2023-05-22 11:10 +0200
          Re: netmask question coreyh@free.fr - 2023-05-22 12:20 +0200
            Re: netmask question Timothy M Butterworth <timothy.m.butterworth@gmail.com> - 2023-05-22 12:30 +0200
            Re: netmask question Dan Ritter <dsr@randomstring.org> - 2023-05-22 13:10 +0200
      Re: netmask question Timothy M Butterworth <timothy.m.butterworth@gmail.com> - 2023-05-22 12:20 +0200
        Re: netmask question Tim Woodall <debianuser@woodall.me.uk> - 2023-05-22 12:30 +0200
        Re: netmask question <tomas@tuxteam.de> - 2023-05-22 13:10 +0200
  Re: netmask question Charles Curley <charlescurley@charlescurley.com> - 2023-05-22 05:10 +0200
  Re: netmask question <tomas@tuxteam.de> - 2023-05-22 07:00 +0200
    Re: netmask question Tim Woodall <debianuser@woodall.me.uk> - 2023-05-22 09:40 +0200
      Re: netmask question <tomas@tuxteam.de> - 2023-05-22 10:00 +0200
      Re: netmask question Timothy M Butterworth <timothy.m.butterworth@gmail.com> - 2023-05-22 12:20 +0200
      Re: netmask question gene heskett <gheskett@shentel.net> - 2023-05-22 18:20 +0200
        Re: netmask question <tomas@tuxteam.de> - 2023-05-22 21:10 +0200
          Re: netmask question gene heskett <gheskett@shentel.net> - 2023-05-23 01:50 +0200
            Re: netmask question Dan Purgert <dan@djph.net> - 2023-05-23 03:20 +0200
              Re: netmask question debian-user@howorth.org.uk - 2023-05-23 12:50 +0200
                Re: netmask question Dan Purgert <dan@djph.net> - 2023-05-23 14:20 +0200
            Re: netmask question tomas@tuxteam.de - 2023-05-23 07:00 +0200
          Re: netmask question "Tom Reed" <tom@dkinbox.com> - 2023-05-23 01:50 +0200
            Re: netmask question Greg Wooledge <greg@wooledge.org> - 2023-05-23 02:10 +0200
              Re: netmask question <tomas@tuxteam.de> - 2023-05-23 06:40 +0200
            Re: netmask question Dan Ritter <dsr@randomstring.org> - 2023-05-23 02:30 +0200
              Re: netmask question "Tom Reed" <tom@dkinbox.com> - 2023-05-23 02:30 +0200
                Re: netmask question Dan Ritter <dsr@randomstring.org> - 2023-05-23 02:50 +0200
                Re: netmask question <tomas@tuxteam.de> - 2023-05-23 06:50 +0200
                Re: netmask question Andy Smith <andy@strugglers.net> - 2023-05-27 03:10 +0200
                Re: netmask question Greg Wooledge <greg@wooledge.org> - 2023-05-27 03:10 +0200
                Re: netmask question Andy Smith <andy@strugglers.net> - 2023-05-27 03:20 +0200
                Re: netmask question Greg Wooledge <greg@wooledge.org> - 2023-05-23 02:50 +0200
                Re: netmask question "Tom Reed" <tom@dkinbox.com> - 2023-05-23 03:00 +0200
                Re: netmask question Dan Ritter <dsr@randomstring.org> - 2023-05-23 03:20 +0200
                Re: netmask question Tim Woodall <debianuser@woodall.me.uk> - 2023-05-23 08:30 +0200
                Re: netmask question Timothy M Butterworth <timothy.m.butterworth@gmail.com> - 2023-05-23 02:50 +0200

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