On 02/02/11 01:41, Noel Jones wrote:
On 2/1/2011 7:18 PM, Dean Gibson (Mail Administrator) wrote:
Running postfix-2.2.10-1.2.1.el4_7.centos:
When I try to send eMail to a person who uses Yahoo! as their
eMail provider, but to a non-Yahoo domain, I get:
Feb 1 16:34:59 mail postfix/smtp[10551]: 8CE431140DB: host
mx1.biz.mail.yahoo.com[68.142.202.129] said: 451 Resources
temporarily not available - Please try again later [#4.16.5].
(in reply to end of DATA command)
Postfix tried the first MX it found. This server was too busy and
deferred the message.
Feb 1 16:35:00 mail postfix/smtp[10551]: 8CE431140DB:
to=<u...@example.com>,
relay=mx1.biz.mail.yahoo.com[74.6.140.31], delay=2,
status=sent (250 ok dirdel)
Postfix tried another MX and it was accepted. (250 ok dirdel) is Yahoo's
acceptance code.
At this point, the mail is in yahoo's hands.
Maybe it was delivered to the recipient's spam folder? At any rate,
postfix has done its job.
I've seen the same thing in the UK with British Telecom (BT), whose
email was outsourced to Yahoo. BT customers traditionally used POP3 to
retrieve mail and, after the outsourcing, had no idea webmail even
existed let alone there might be some spam folder containing their
missing mail. It took a while for the penny to drop.
Being a small (home) sender, I found a solution to use
/etc/postfix/transport to selectively relay mail through my ISP smtp
servers for "difficult" domains. For example:
/etc/postfix/transport
# Relay mail for these domains through ISP smarthost
btinternet.com smtp:[outmail.myisp.com]:25
yahoo.co.uk smtp:[outmail.myisp.com]:25
yahoo.com smtp:[outmail.myisp.com]:25
then postmap /etc/postfix/transport && postfix reload.
When relaying outbound mail through my ISP I no longer had an issue with
mail occasionally being classified as spam by Yahoo.
