Hi Friends, Some days back I strated gettings calls for the non delivery to some selected domains , I have taken one affected domain as an example here that is "Progression.com". If I use the DNS ip address provided by ISP that is 202.56.230.5 as as external lookup server in EDGE server it always try to send mail to ip address: 72.34.61.124 which is not mapped to any mx record for this domain. Here is the extract from send logs 72.34.61.124:25 < 250 OK 72.34.61.124:25 < 550-mail1.medanta.org [61.247.254.78]:57210 is currently not permitted to relay 72.34.61.124:25 < 550-through this server. Perhaps you have not logged into the pop/imap server 72.34.61.124:25 < 550-in the last 30 minutes or do not have SMTP Authentication turned on in your 72.34.61.124:25 < 550 email client. If I use any other DNS lets say Google's open DNS that is 8.8.8.8 then mail always go without any issues and hit the right mx record , here is the extract: 213.229.71.209:25 < 250 2.1.0 Ok 213.229.71.209:25 < 250 2.1.5 Ok 213.229.71.209:25 < 250 2.1.5 Ok 213.229.71.209:25 > DATA 213.229.71.209:25 < 354 End data with <CR><LF>.<CR><LF> 213.229.71.209:25 < 250 2.0.0 Ok: queued as F19EE190911 213.229.71.209:25 > QUIT 213.229.71.209:25 < 221 2.0.0 Bye 213.229.71.209:25 - Please look at the nslookup result below from both DNS servers which seems to be quite similar except that are the some additional NS record shown the query made to 202.56.230.5 , is it ISP DNS issue or Exchange where is wrongly picking NS record for SMTP.?? ============ Query to 202.56.230.5============ C:\Users\yogesh.malhotra>nslookup Default Server: medggn-ms-dc.medanta.com Address: 10.1.62.10 > server 202.56.230.5 DNS request timed out. timeout was 2 seconds. Default Server: [202.56.230.5] Address: 202.56.230.5 > set q=soa > progression.com Server: [202.56.230.5] Address: 202.56.230.5 *** [202.56.230.5] can't find progression.com: Server failed > set q=mx > progression.com Server: [202.56.230.5] Address: 202.56.230.5 Non-authoritative answer: progression.com MX preference = 20, mail exchanger = mail2.qlc.co.in progression.com MX preference = 30, mail exchanger = mail3.qlc.co.in progression.com MX preference = 10, mail exchanger = mail1.qlc.co.in progression.com nameserver = ns2.pvcpartners.in progression.com nameserver = ns1.pvcpartners.in mail3.qlc.co.in internet address = 121.241.242.32 ns2.pvcpartners.in internet address = 72.34.61.124 ns1.pvcpartners.in internet address = 72.34.61.123 =================================================== ================ Query to GOOGLE's 8.8.8.8================== Default Server: medggn-ms-dc.medanta.com Address: 10.1.62.10 > server 8.8.8.8 DNS request timed out. timeout was 2 seconds. Default Server: [8.8.8.8] Address: 8.8.8.8 > server 8.8.8.8 Default Server: google-public-dns-a.google.com Address: 8.8.8.8 > set q=mx > progression.com Server: google-public-dns-a.google.com Address: 8.8.8.8 Non-authoritative answer: progression.com MX preference = 30, mail exchanger = mail3.qlc.co.in progression.com MX preference = 10, mail exchanger = mail1.qlc.co.in progression.com MX preference = 20, mail exchanger = mail2.qlc.co.in ======================================================= Yogesh Malhotra http://flickr/photos/yogeshmalhotra

Hi, This is a DNS issue. It seems that your ISP's DNS is the culprit and providing wrong MX details. As you said that from last few days you are facing this problem, this behaviour could also be possible if "Progression.com" domain has changed their MX pointers to some other IP addresses and the same information is updated in Google's DNS but not in your ISP DNS. Exchange is not wrong here as it will only send a mail to the MX record it gets from the DNS. Regards Supreet Singh Supreet Singh

Hi, Do you have any update? ThanksSophia Xu