I also find your usage of 'our' to be quite strange. Please try stevieb's advise to see if your error goes away by using 'my $host = ...'. Additionally I recommend to rewrite your get_local_ip function as follows:

minimum - use return value to provide 'local ip' 
sub get_local_ip {
   my $sock = IO::Socket::INET->new(
    PeerAddr=> $mrtgc2,
    PeerPort=> 5432,
    Proto   => "tcp");

  return $sock->sockhost;
}

my $localip = get_local_ip();

[download]
refinement - with extracted parameters: 
sub get_local_ip {
  my $host = shift;
  my $port = shift;

   my $sock = IO::Socket::INET->new(
    PeerAddr=> $host,
    PeerPort=> $port,
    Proto   => "tcp");

  return $sock->sockhost;
}

my $localip = get_local_ip($mrtgc2, 5432);

[download]

In reply to Re: Uninitialized value from hostname() by Monk::Thomas
in thread Uninitialized value from hostname() by eepstein

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