protected function srvGet($domain, $https = false)
    {
        // Are we going secure? Set up a fallback too.
        if (isset($https) && $https === true) {
            $subdomain = '_avatars-sec._tcp.';
            $fallback  = 'seccdn.';
            $port      = 443;
        } else {
            $subdomain = '_avatars._tcp.';
            $fallback  = 'cdn.';
            $port      = 80;
        }

        if ($domain === null) {
            // No domain means invalid email address/openid
            return $fallback . 'libravatar.org';
        }

        // Lets try get us some records based on the choice of subdomain
        // and the domain we had passed in.
        $srv = dns_get_record($subdomain . $domain, DNS_SRV);

        // Did we get anything? No?
        if (count($srv) == 0) {
            // Then let's try Libravatar.org.
            return $fallback . 'libravatar.org';
        }

        // Sort by the priority. We must get the lowest.
        usort($srv, array($this, 'comparePriority'));

        $top = $srv[0];
        $sum = 0;

        // Try to adhere to RFC2782's weighting algorithm, page 3
        // "arrange all SRV RRs (that have not been ordered yet) in any order,
        // except that all those with weight 0 are placed at the beginning of
        // the list."
        shuffle($srv);
        $srvs = array();
        foreach ($srv as $s) {
            if ($s['weight'] == 0) {
                array_unshift($srvs, $s);
            } else {
                array_push($srvs, $s);
            }
        }

        foreach ($srvs as $s) {
            if ($s['pri'] == $top['pri']) {
                // "Compute the sum of the weights of those RRs"
                $sum += (int) $s['weight'];
                // "and with each RR associate the running sum in the selected
                // order."
                $pri[$sum] = $s;
            }
        }

        // "Then choose a uniform random number between 0 and the sum computed
        // (inclusive)"
        $random = rand(0, $sum);

        // "and select the RR whose running sum value is the first in the selected
        // order which is greater than or equal to the random number selected"
        foreach ($pri as $k => $v) {
            if ($k >= $random) {
                $target = $v['target'];
                if ($v['port'] !== $port) {
                    $target.= ':'. $v['port'];
                }
                return $target;
            }
        }
    }