Problems sending mail to yahoo?

Raymond L. Corbin rcorbin at
Thu Apr 10 19:28:17 UTC 2008


I have had to tell some dedicated server clients that they will need to disable their forwards to Yahoo or add something like postini for those accounts that forward to Yahoo...It generally works...however Yahoo! for the past three months is now blocking entire /24's if a few IP's get complaints. They have the feedback loops however when you have a network with 175,000 IP addresses and you sign up for a feedback loop for them all they tend to flood your abuse desk with false positives, or forwarded spam. They also don't keep track of which IP's are getting the complaints for you to investigate after the block on the /24 so asking them won't help :(. This potentially means one customer could easily effect the other customer. They offer whitelisting, but this won't get you passed their blocks on the entire /24. They apparently will eventually accept the message because they aren't necessarily 'blocked' but they are 'depriortized' meaning they don't believe your IP is important enough to deliver the message at that time, so they want you to keep trying and when their servers are not 'busy' or 'over loaded' they will accept the message. (Paraphrased from conversations with their 'Bulk Mail Advocacies and Anti-Abuse manager.)


-----Original Message-----
From: owner-nanog at [mailto:owner-nanog at] On Behalf Of Chris Stone
Sent: Thursday, April 10, 2008 1:49 PM
To: nanog at
Subject: Re: Problems sending mail to yahoo?

Hash: SHA512

Barry Shein wrote:
> Is it just us or are there general problems with sending email to
> yahoo in the past few weeks? Our queues to them are backed up though
> they drain slowly.
> They frequently return:
>        421 4.7.0 [TS01] Messages from MAILSERVERIP temporarily deferred due to user complaints -; see
>     (where MAILSERVERIP is one of our mail server ip addresses)
> Just wondering if this was a widespread problem or are we just so
> blessed, and any insights into what's going on over there.

I see this a lot also and what I see causing it is accounts on my servers
that don't opt for spam filtering and they have their accounts here set to
forward mail to their accounts - spam and everything then gets
sent there - they complain to about the spam and bingo - email
delays from here to accounts....


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Chris Stone, MCSE
Vice President, CTO
AxisInternet, Inc.
910 16th St., Suite 1110, Denver, CO 80202
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PH  303.592.AXIS x302  -  866.317.AXIS  |  FAX  303.893.AXIS
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cstone at                        |
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