Re: About named port binding

From: Blazej Kantak (parowka@vlo.ids.gda.pl)
Date: 01/04/02


Date: Fri, 4 Jan 2002 16:49:12 +0100 (CET)
From: Blazej Kantak <parowka@vlo.ids.gda.pl>
To: chulmin <chulmin@etc.co.kr>

On Thu, 3 Jan 2002, chulmin wrote:

> Hello, all.
>
> I know that only root account bind a port below 1024.
> and anyuser except root can bind or use a port above 1024.
> But named process uses udp port 53 with named uid.
> How can it be possible?
> and is it illegal or exception?

not at all. I assume that U starts named with -u option.
After named port binding, it runs seteuid function to change
process EUID. But when U send SIGHUP to named, it won't rescan active
interfaces, because it's euid is not equal 0. Process will just terminate.

                                        b. Parowka K.

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Email address : pascal@ids.gda.pl
        "Everything what we do see is a past"
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Relevant Pages

  • Re: About named port binding
    ... >> I know that only root account bind a port below 1024. ... >> and anyuser except root can bind or use a port above 1024. ... > Heh, it isn't that simple, with POSIX 1.e capabilities. ...
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  • About named port binding
    ... I know that only root account bind a port below 1024. ... and anyuser except root can bind or use a port above 1024. ... But named process uses udp port 53 with named uid. ...
    (Focus-Linux)