Oct  9 08:50:53 mail_server sendmail[30172]: j99FopoN030172: from=<support@symantec.com>, size=0, class=0, nrcpts=0, proto=ESMTP, daemon=MTA, relay=[218.1.114.182]

##</code><code>##

if ($line =~ /relay\=\[?(.*?)\]?/) {
    $server = $1;
}

##</code><code>##

if ($line =~ /relay\=(.*?)/) {
    $server = $1;
}