On 31 Oct 2006 at 16:02, Randy Ryan wrote:

> I was told that Yahoo wasn't delivering any email from Syracuse for a couple of 
> days, and sure enough, all mail from the domain (including sending THANKS and 
> INFO commands) are not being delivered; the list admin verified Yahoo isn't 
> accepting much.
> 
> So, I bcc'd all yahoo users on 3 lists of the block to let them know what was 
> going on.  I had about 15 bad yahoo addresses for no user.  Should the listserv 
> software be able to process those rejection notices?  Do people periodically 
> turn off the automated processing to cull out non-deliverable addresses 
> listserv isn't catching?

Yahoo incorrectly uses a 541 error code for bad addresses. This code 
means that there is a transactional problem with the specific email 
message rather than with the address -- in other words, the address 
is fine but this particular message can never be delivered. So by 
default, LISTSERV _correctly_ does NOT use that error code for auto-
delete. 

There is a site-wide parameter that you can set to force LISTSERV to 
treat ALL 5xx codes as permanent bounces, but WATCH OUT -- if you use 
it, you may see valid AOL.COM addresses getting autodeleted because 
AOL uses that error code the way it's supposed to be used: to 
indicate a transactional error, for example to reject an email based 
on contents. I mentioned this to an AOL.COM postmaster, and she said 
she would have to talk to Yahoo! about that, but I never heard back 
from her, and Yahoo! has not changed their wicked ways.

Probes should eventually catch the bad Yahoo.com addresses, but Yahoo 
is really aggressive so it may start blocking before the probes 
trigger an auto-delete, and then you end up auto-deleting all your 
Yahoo addresses.

Solution is to live with re-adding aol.com addresses every once in a 
while, or to manually purge bad yahoo.com addresses from lists. If 
the site is using L-Soft HDMail for deliveries, that can simplify the 
latter.

-- 
Francoise Becker

There is only one LISTSERV(R) -- the product that launched the 
email list communication industry in 1986. To discover the 
story behind LISTSERV, visit:
http://www.lsoft.com/corporate/20anniversary.asp