4xx - try again later. In my experience you'll not be told anything more - except perhaps to hint that you should be using Yahoo's DomainKeys. - steve From: nznog-bounces(a)list.waikato.ac.nz [mailto:nznog-bounces(a)list.waikato.ac.nz] On Behalf Of Cameron Bradley Sent: Thursday, 7 April 2011 2:48 p.m. To: NZNOG Mailing-List Subject: [nznog] Xtra's strange MTA behaviour. Hey guys, Wondering if any of you had ever encountered this lovely little bit of 'filtering' on Xtra's behalf. When my mail gateway (non-blacklisted, mail accepted by everyone) attempts to contact Xtra's MTA, the following is the response: wiretap(a)mx-e1:~$ telnet mta.xtra.co.nz 25 Trying 210.54.141.1... Connected to mta.xtra.co.nz. Escape character is '^]'. 421 Service not available Connection closed by foreign host. Now that is an instant disconnection, with no opportunity to submit recipient or sender details, which is making it very hard to send email to xtra customers. Perhaps someone from Xtra would like to help out, or someone on here has an idea of 'resolving' this issue? Regards, Cameron Bradley ========================================================= This e-mail has been scanned for Viruses and Content and cleared by Mail Marshal