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Groups > linux.debian.user > #168620

Re: make ping executable by normal users?

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On Mon 06 Jun 2016 at 15:27:16 (+0000), Mark Fletcher wrote:
> On Mon, 6 Jun 2016 at 23:15, Santiago Vila <sanvila@unex.es> wrote:
> 
> > On Mon, Jun 06, 2016 at 10:06:54AM +1200, Jan Bakuwel wrote:
> > > Check your firewall rules.
> >
> > It can't be firewall rules. Try this to block outgoing ping:
> >
> > iptables -A OUTPUT -p icmp --icmp-type echo-request -j REJECT
> >
> > then try to ping anywhere. You will get a different error message,
> > namely "Destination Port Unreachable".
> >
> > [ Why people do not read all messages in the thread before answering
> >   is a mystery to me ].

> No, that's not true, you definitely can get this very error due to
> something to do with the firewall, maybe it's not able to resolve the ping
> target rather than not able to reach the resulting host, I'm damned if I
> can remember the specifics but I've definitely seen this happen on an lfs
> box before and it was nothing to do with perms (as I said before, to your
> point about people not reading the whole thread...)

I don't understand this argument.

Why would ping bother to open a socket to a host it couldn't resolve?

I know precious little about firewall rules, but AIUI the rules
determine whether to respond with things like Drop, Reject, Deny.
Now the OP didn't manage to open a socket; that's in the error message:
"ping: icmp open socket: Operation not permitted"
So how would ping find out how the firewall was going to react to its
ping message without opening a socket to send something?

Cheers,
David.

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Thread

make ping executable by normal users? Britton Kerin <britton.kerin@gmail.com> - 2016-06-03 00:00 +0200
  Re: make ping executable by normal users? Lisi Reisz <lisi.reisz@gmail.com> - 2016-06-03 00:30 +0200
    Re: make ping executable by normal users? Santiago Vila <sanvila@unex.es> - 2016-06-03 01:20 +0200
  Re: make ping executable by normal users? Santiago Vila <sanvila@unex.es> - 2016-06-03 01:00 +0200
    Re: make ping executable by normal users? Britton Kerin <britton.kerin@gmail.com> - 2016-06-08 01:00 +0200
      Re: make ping executable by normal users? David Wright <deblis@lionunicorn.co.uk> - 2016-06-08 02:20 +0200
      Re: make ping executable by normal users? Santiago Vila <sanvila@unex.es> - 2016-06-08 03:00 +0200
      Re: make ping executable by normal users? Adam Borowski <kilobyte@angband.pl> - 2016-06-08 13:20 +0200
      Re: make ping executable by normal users? Ben Hutchings <ben@decadent.org.uk> - 2016-06-08 15:50 +0200
        Re: make ping executable by normal users? Santiago Vila <sanvila@unex.es> - 2016-06-08 16:40 +0200
  Re: make ping executable by normal users? Mark Fletcher <mark27q1@gmail.com> - 2016-06-03 04:00 +0200
  Re: make ping executable by normal users? Jan Bakuwel <jan.bakuwel@omiha.com> - 2016-06-06 00:10 +0200
    Re: make ping executable by normal users? Norbert Kiszka <norbert@linux.pl> - 2016-06-06 00:30 +0200
    Re: make ping executable by normal users? Santiago Vila <sanvila@unex.es> - 2016-06-06 16:20 +0200
      Re: make ping executable by normal users? Mark Fletcher <mark27q1@gmail.com> - 2016-06-06 17:30 +0200
        Re: make ping executable by normal users? David Wright <deblis@lionunicorn.co.uk> - 2016-06-06 18:10 +0200
          Re: make ping executable by normal users? Norbert Kiszka <norbert@linux.pl> - 2016-06-06 18:20 +0200
            Re: make ping executable by normal users? David Wright <deblis@lionunicorn.co.uk> - 2016-06-06 18:30 +0200
              Re: make ping executable by normal users? Norbert Kiszka <norbert@linux.pl> - 2016-06-06 18:40 +0200
                Re: make ping executable by normal users? David Wright <deblis@lionunicorn.co.uk> - 2016-06-06 19:10 +0200
                Re: make ping executable by normal users? Norbert Kiszka <norbert@linux.pl> - 2016-06-06 20:00 +0200
                Re: make ping executable by normal users? David Wright <deblis@lionunicorn.co.uk> - 2016-06-06 21:10 +0200
                Re: make ping executable by normal users? Norbert Kiszka <norbert@linux.pl> - 2016-06-06 21:40 +0200
        Re: make ping executable by normal users? Santiago Vila <sanvila@unex.es> - 2016-06-06 18:10 +0200
      Re: make ping executable by normal users? Reco <recoverym4n@gmail.com> - 2016-06-06 17:50 +0200
        Re: make ping executable by normal users? David Wright <deblis@lionunicorn.co.uk> - 2016-06-06 18:20 +0200
          Re: make ping executable by normal users? Reco <recoverym4n@gmail.com> - 2016-06-06 18:30 +0200
            Re: make ping executable by normal users? David Wright <deblis@lionunicorn.co.uk> - 2016-06-06 18:40 +0200
              Re: make ping executable by normal users? Reco <recoverym4n@gmail.com> - 2016-06-07 16:00 +0200
                Re: make ping executable by normal users? Nicolas George <george@nsup.org> - 2016-06-07 17:10 +0200

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