Hi All

We are experiencing problems delivering mails for domains having their MX record set to mx-eu.mail.am0.yahoodns.net (for example yahoo.it, yahoo.de, yahoo.co.uk). So far we have figured out that Yahoo’s DNS servers send different responses. Depending on the DNS response we are able to establish SMTP connections. Below example shows 2 servers from their DNS that seems to accept SMTP connections:

[root@x1:~] # dig a mx-eu.mail.am0.yahoodns.net @yf2.yahoo.com +short
188.125.72.73
188.125.72.74

[root@x1:~] # telnet 188.125.72.73 25
Trying 188.125.72.73...
Connected to mtaproxy1.free.mail.vip.ir2.yahoo.com.

[root@x1:~] # telnet 188.125.72.74 25
Trying 188.125.72.74...
Connected to mtaproxy2.free.mail.vip.ir2.yahoo.com.

On the other hand we sometimes get other replies from the “same” (the id.server chaos record tell’s us it’s a different one) DNS server with different A records that do not accept SMTP connections:

[root@x1:~] # dig a mx-eu.mail.am0.yahoodns.net  @yf2.yahoo.com +short
188.125.73.87
212.82.101.46

[root@x1:~] # telnet 188.125.73.87 25
Trying 188.125.73.87...
telnet: connect to address 188.125.73.87: Operation timed out
telnet: Unable to connect to remote host

[root@x1:~] # telnet 212.82.101.46 25
Trying 212.82.101.46...
telnet: connect to address 212.82.101.46: Operation timed out
telnet: Unable to connect to remote host

We have so far confirmed this behaviour from different AS (Hetzer, OVH). Does anybody else experiencing the same behaviour?

We have tried to contact their postmaster address and few others we found on the internet. Unfortunately so far no one was really able to help us. The Yahoo Small Business Phone Number that has been posted on this list back in October 2009 seems no longer to be in operations too. Therefore if you know how to get in touch with their technical staff that would be much appreciated.

Best Regards
Dominic Schlegel