Re: [MacPerl] TCP/IP address

[ajf@afco.demon.co.uk (Alan Fry)]

>}Hi there,
>}
>}I have a script that wants to run over a dialup PPP connection. The script
>}needs to know the TCP address of the mac on which it is running, but that
>}address is dynamic, being set at connect time. How can one find that
>}information from within macperl?
>
>You really want the address, or just the name?
>
>chomp($myname = `hostname`);
>$myaddr = (gethostbyname($myname))[4];
>$mynum = join(".",unpack(C4,$myaddr));
>print "$myname $mynum\n";
>
>gives me (correctly) at the moment on my dynamic PPP connection:
>
[...]

The script probably will not know either the domain name or the address of
the machine on which it is running. Therefore you may have to open a
connection to some remote site and ask it to tell you who you are using
'getsockname()'. The following works here:

        #!perl
        $remote = (gethostbyname('remote.host'))[4];
        $p_add = pack('S n a4 x8', 2, $port, $remote);
        socket(SOCK, 2, 1, 6) or die "$!\n";
        connect(SOCK, $p_add) or die "$!\n";
        $myname = getsockname(SOCK);
        $myaddr = (unpack('S n a4 x8', $myname))[2];

$myaddr will then return the packed net address of the machine on which the
script is running. [$port will of course depend on the server protocol,
'smtp, 'ftp' 'domain' or whatever, and can be looked up in
'getservbyname(PROTONAME, 'tcp')']

Hope this helps.

Alan Fry

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