How many soft and hard bounces before I should remove addresses from my list?

popowich

EQ Forum Admin
Staff member
Hello,

I was recently asked:

Yahoo asks how many soft and hard bounces I receive before I remove them from my list, what is the industry recommendation?My answer is:

It's OK to resend a few times to accounts that 4xx "soft bounced"

You should immediately remove any 5xx "hard bounces"
 

nkitson

New Email
You should immediately remove any 5xx "hard bounces"
I do, but, what would you do with something like

failed,5.0.0 (undefined status),"smtp;521 5.2.1 ""TempFail""

This address (an aol.com address) was regularly receiving emails without a problem until this one pops up. The address itself is valid. Our service is pretty 'clean' (own IP, DKIM, domain keys, spf, we react to fbls within a few days, and our content is newsletters and similar material from schools to parents)

This is a typical example of 5xx bounces that happen a lot where the 'English' - ie "undefined status" and "TempFail" do not suggest a need to remove them from our db.
 

nkitson

New Email
Thanks for the quick response!

I will pm our IP and other details that I have anonomised below.


timeLogged orig rcpt|dsnAction|dsnStatus|dsnDiag|dsnMta|bounceCat|srcType|srcMta|dlvType |dlvSourceIp dlvDestinationIp dlvEsmtpAvailable dlvSize queue

28/09/2012 17:30
me@mydomain.com them@aol.com |failed|5.0.0 (undefined status)|smtp;521 5.2.1 "TempFail" | mailin-04.mx.aol.com (64.12.90.66)|other| smtp| myServer (127.0.0.1) |smtp |1.1.1.1 64.12.90.66 DSN 2524620 aol.com/{default}

The log is created by PowerMTA and I'm inclined to trust it. Sorry if its difficult to line up headers and log entry

Cheers,
Nick
 

popowich

EQ Forum Admin
Staff member
Hi Nick,

It looks like a valid AOL address to me:

rcpt to:<"them"@aol.com> (real address tested)
250 2.1.5 Ok

I do not see your IP on any blacklists.

I believe the tempfail came from your software or something between it and AOL, not from AOL itself

Stab in the dark, is it possible your mailer ran out of resources?

Did any other addresses unexpectedly start temp failing with unknown status at the same time?
 

nkitson

New Email
Don't think that's the answer - I've looked for the 'TempFail' in our logs and found 27 over the last 2 weeks (the time we keep this level of detail). All were to different aol.com addresses and from half a dozen different aol mailservers.

No clues in the time of day either, times were spread over the day from our server being lightly loaded at 8am to busy periods mid afternoon.

Given that 'TempFail' is only being associated with aol recipients, it seems to point back to them... Any other thoughts?
 

nkitson

New Email
I don't think that was it. I checked our logs for just "TempFail" over the last 2 weeks and found 27 instances, all to AOL addresses, and with 12 different AOL mailserver IP addresses.

No correlation with time of day either - we got them at 8am when we are quiet as well as our peak periods.

Any other thoughts?
 

popowich

EQ Forum Admin
Staff member
Telnet to some AOL MX servers, what is the response?

;; ADDITIONAL SECTION:
mailin-01.mx.aol.com. 3600 IN A 64.12.90.98
mailin-01.mx.aol.com. 3600 IN A 205.188.59.194
mailin-01.mx.aol.com. 3600 IN A 205.188.146.193
mailin-01.mx.aol.com. 3600 IN A 205.188.159.42
mailin-01.mx.aol.com. 3600 IN A 64.12.90.1
mailin-02.mx.aol.com. 3600 IN A 205.188.103.1
mailin-02.mx.aol.com. 3600 IN A 205.188.155.110
mailin-02.mx.aol.com. 3600 IN A 205.188.190.1
mailin-02.mx.aol.com. 3600 IN A 64.12.90.65
mailin-02.mx.aol.com. 3600 IN A 64.12.139.193
mailin-03.mx.aol.com. 3600 IN A 205.188.156.193
mailin-03.mx.aol.com. 3600 IN A 205.188.190.2
mailin-03.mx.aol.com. 3600 IN A 64.12.90.33
mailin-03.mx.aol.com. 3600 IN A 64.12.90.97
mailin-03.mx.aol.com. 3600 IN A 205.188.59.193
mailin-04.mx.aol.com. 3600 IN A 205.188.146.194
mailin-04.mx.aol.com. 3600 IN A 64.12.90.34
mailin-04.mx.aol.com. 3600 IN A 64.12.90.66
mailin-04.mx.aol.com. 3600 IN A 64.12.138.161
mailin-04.mx.aol.com. 3600 IN A 205.188.103.2


> telnet 64.12.90.98 25
Trying 64.12.90.98...
Connected to 64.12.90.98.
Escape character is '^]'.
220-mtain-md01.r1000.mx.aol.com ESMTP Internet Inbound
220-AOL and its affiliated companies do not
220-authorize the use of its proprietary computers and computer
220-networks to accept, transmit, or distribute unsolicited bulk
220-e-mail sent from the internet.
220-Effective immediately:
220-AOL may no longer accept connections from IP addresses
220 which no do not have reverse-DNS (PTR records) assigned.


Do you get dropped right away with an error or do they accept the manual telnet to port 25 from you?
 

nkitson

New Email
They accept a manual connection from our IP. I would be surprised if they didn't, we have nearly 10,000 aol addresses on our db and manage to deliver to most.
 
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