Yeah they and a few others started doing this not too long ago (few months). I thought perhaps something common got upgraded/patched but then I just thought that it was a rather odd configuration change.. It certainly is new. A chap I know (for some reason) set his source port for queries to be port 53 and his DNS queries started to fail. -- Leigh -----Original Message----- From: owner-nanog@merit.edu on behalf of Chris Edwards Sent: Wed 4/25/2007 10:43 PM To: nanog@merit.edu Subject: Re: Hotmail blackholing certain IP ranges ? Some sites have recently reported problems mailing hotmail due to inability to resolve the hotmail MX records. This appears to be due to the hotmail DNS servers now blackholing DNS queries where the UDP source port was < 1024. I can reproduce this here and now, but don't know if it's new. Chris -- Chris Edwards, Glasgow University Computing Service