[Mailman-Users] Rejected Confirmation Requests

[Mark Gillingham]

I fear that some potential list members are unable to get confirmation 
requests  through. I've verified that I can subscribe and unsubscribe 
from 3 of my accounts, but on a fourth (at yahoo) I cannot confirm my 
subscription. Instead, I get the following information in my mallog:

Sep  9 19:31:28 gbf1 sendmail[3672]: g8A0VRx03672: tcpwrappers 
(web20405.mail.yahoo.com, 66.163.169.93) rejection

Sep  9 19:31:28 gbf1 sendmail[3672]: NOQUEUE: web20405.mail.yahoo.com 
[66.163.169.93] did not issue MAIL/EXPN/VRFY/ETRN during connection to 
MTA

How should I set the sendmail configuration to accept these messages? 
Is this hosts.allow or sendmail.cf? I still get confused.

Mark