<?php

$ch = curl_init("http://somesite.com/redir1.php");

curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);

curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

$resp = curl_exec($ch);

echo curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);

curl_close($ch);