up vote 0 down vote favorite
share [g+] share [fb]

I have a user that cannot authenticate. What I am getting is:

did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA

I have SASL installed for plaintext passwords. Can someone please point me in the right direction? What am I missing?

link|improve this question
1. The error message does not have anything to do with authentication. 2. Neither does TLS (if you are using SASL for auth). – grawity Mar 4 '11 at 6:21
feedback

1 Answer

up vote 0 down vote

The error message means that the client opens up a connection to port 25 on your server, but does not issue any other commands. I will make a wild guess here and will suspect that this is a TCP window scaling problem. If the client is a Windows Vista / 7 machine try something like:

netsh interface tcp set global autotuninglevel=disabled

or

netsh interface tcp set global autotuninglevel=restricted

from a command prompt that you have started as an administrator. If your server is a linux machine you can try adding these at the bootom of your /etc/sysctl.conf:

 net.ipv4.tcp_rmem = 4096 87380 174760
 net.ipv4.tcp_wmem = 4096 16384 131072
 net.ipv4.tcp_window_scaling = 0

Run "sysctl -p" as root for the changes to take effect. Depending the case you may need both. However this is a workaround and not a solution to the problem, and like I said a wild guess since I've seen such behaviour coupled with the error message that you describe too many times.

link|improve this answer
feedback

Your Answer

 
or
required, but never shown
discard

Not the answer you're looking for? Browse other questions tagged or ask your own question.