qmail - 421 unable to read controls

NodeWorx General Discussion
1

Hello All,

I’m wondering if any of you interworx folk get this error when sending email.

Konto: ‘username@domainname.com’, Server: ‘mail.domainname.com’, Protokoll: SMTP, Serverantwort: ‘421 unable to read controls (#4.3.0)’, Port: 25, Secure (SSL): Nein, Serverfehler: 421, Fehlernummer: 0x800CCC67

(I know its in german but you can still get the error)

Information I have found on the net:
qmail-smtpd-auth-0.31 has a minor bug if you use morercpthosts. After a failed authentication attempt, if the client attempts to send mail to a domain which is not listed in rcpthosts, qmail-smtpd is unable to read morercpthosts.cdb. Instead, it sends “421 unable to read controls (#4.3.0)” and drops the connection. qmail-smtpd-auth-close3.patch fixes this bug by closing file descriptor 3 (only if necessary) in the authentication child process rather than the parent process.

Any ideas if this is the case? I have the latest version of interworx running on my server.
InterWorx-CP v2.1.3
qmail 1.03

Thanks!

2

I doubt it’s the auth bug you mention - if it were we would have seen it before. My guess without looking at the box is permissions on the qmail dirs and/or files. If you can’t figure it out you may want to open a support ticket.

Paul

3

Uhm if its permissions - then its constantly changing - Customer says it doesn’t happen often but periodically.

4

why would permissions change occasionally? Any solutions?

5

Permissions shouldn’t change occasionally. Were you able to track it down to permissions problem? Maybe it’s a memory limit problem. You could try increasing the /service/smtp/run file’s memory limit. It looks like

exec /usr/bin/softlimit -m SOME-NUMBER-HERE \

you could try doubling the SOME-NUMBER.

Is the problem easily reproducable or completely random? Random sounds like memory limit is a possiblity.