sendmail FAQ

sendmail FAQ

am 25.01.2008 21:00:01 von John Beck

Posted-By: auto-faq 3.3 (Perl 5.008)
Archive-name: mail/sendmail/faq
Posting-Frequency: posted on the 10th and 25th of each month
Last-modified: November 4, 2007
Maintainer: Sendmail FAQ

Frequently Asked Questions (FAQ)

Last updated November 4, 2007

Changes since the last post on 10 Jan 2008 12:00:01 PST
* none

Top 5 - the *most* frequently asked questions about sendmail:

1. Local config error: see 4.5
2. Relaying denied: see 3.27
3. Directory permissions: see 3.33
4. Virtual hosting: see 3.7 & 3.28
5. POP / IMAP: see 4.19

Table of Contents

* 0. Plain-text version of the entire FAQ available at:



+ 2.1 What is this newsgroup?
+ 2.2 What is the scope of this FAQ?
+ 2.3 Where can I find the latest version of this FAQ?
+ 2.4 Where can I send comments, questions and bug reports?
+ 2.5 Where can I ask email-related DNS questions?
+ 2.6 How can I subscribe to these newsgroups?
+ 2.7 Which version of sendmail should I run?
+ 2.8 What is the latest release of sendmail?
+ 2.9 Where can I find it?
+ 2.10 What are the differences between Version 8 and other versions?
+ 2.11 What's the best platform for running sendmail?
+ 2.12 What is BIND and where can I get the latest version?
+ 2.13 What is smrsh and where can I get it?
+ 2.14 What is smap and where can I get it?
+ 2.15 What is TCP-Wrappers and where can I get it?
+ 2.16 Why won't db 1.85 build on my machine?
+ 2.17 What is makemap and where can I get it?


+ 3.1 How do I make all my addresses appear to be from a single host?
+ 3.2 How do I rewrite my "From:" lines to read
``First_Last@My.Domain'' or ``Different_Name@My.Domain''?
+ 3.3 But what about fully-qualified addresses, such as those from Pine
or FEATURE(always_add_domain)?
+ 3.4 So what was the user database feature intended for?
+ 3.5 Why the hostility to using full names for email addresses?
+ 3.6 deprecated
+ 3.7 How do I manage several (virtual) domains?
+ 3.8 There are four UUCP mailers listed in the configuration files.
Which one should I use?
+ 3.9 deprecated
+ 3.10 How do I solve "collect: I/O error on connection" or
"reply: read error from" errors?
+ 3.11 Why can't my users forward their mail to a program?
+ 3.12 Why do connections to the SMTP port take such a long time?
+ 3.13 Why do I get "unknown mailer error 5 -- mail: options MUST
PRECEDE recipients" errors?
+ 3.14 Why does version 8 sendmail panic my SunOS box?
+ 3.15 Why does the Unix From line get mysteriously munged when I send
to an alias?
+ 3.16 Why doesn't MASQUERADE_AS (or the user database) work
for envelope addresses as well as header addresses?
+ 3.17 How do I run version 8 sendmail and support the MAIL11V3 protocol?
+ 3.18 Why do messages disappear from my queue unsent?
+ 3.19 When is sendmail going to support RFC 2047 MIME header encoding?
+ 3.20 Why can't I get mail to some places, but instead always get
the error "reply: read error from"?
+ 3.21 Why doesn't "FEATURE(xxx)" work?
+ 3.22 How do I configure sendmail not to use DNS?
+ 3.23 How do I get all my queued mail delivered to my Unix box from
my ISP?
+ 3.24 Why do I get the error message unable to write
+ 3.25 Why can't I compile sendmail with Berkeley DB 2.X?
+ 3.26 What operating systems has Berkeley sendmail been ported to?
+ 3.27 How do I prevent "Relaying Denied" errors for my clients?
+ 3.28 Why isn't virtual hosting working, even after I added a
"Kvirtuser" line to ?
+ 3.29 How can I add a header specifying the actual recipient when having
multiple users in a virtual domain go to a single mailbox?
+ 3.30 What do I do when Build fails because groff was not found?
+ 3.31 What does "class hash not available" mean?
+ 3.32 How do I configure majordomo with sendmail 8.9 without relaxing
the DontBlameSendmail option?
+ 3.33 How do I configure my system in general with sendmail 8.9?
+ 3.34 What does "foo not available for sendmail programs" mean?
+ 3.35 How do I add a footer/signature to all (outgoing) e-mail messages?
+ 3.36 What does "Cannot open hash database ... Invalid argument" mean?
+ 3.37 What does "parse error before `NDBM'" mean?
+ 3.38 What does "may be forged" mean?
+ 3.39 How do I send using an alternate port?
+ 3.40 Why can't I use Berkeley DB 4.1.x?
+ 3.41 How do I use CIDR notation in the access map (or other places)?
+ 3.42 Why isn't CIDR notation directly supported by sendmail?
+ 3.43 What does "Need to recompile with -DNEWDB for hash support" mean?
+ 3.44 I disabled sendmail on some machines which don't receive mail,
but since upgrading to 8.12 they can't *send* mail either; why?


+ 4.1 Should I use a wildcard MX for my domain?
+ 4.2 How can I set up an auto-responder?
+ 4.3 How can I get sendmail to deliver local mail to $HOME/.mail
instead of into /usr/spool/mail (or /usr/mail)?
+ 4.4 Why does it deliver the mail interactively when I'm trying to get
it to go into queue only mode?
+ 4.5 How can I solve "MX list for hostname points back to hostname"
and "config error: mail loops back to myself" messages?
+ 4.6 Why does my sendmail process sometimes hang when connecting over
a SLIP/PPP link?
+ 4.7 How can I summarize the statistics generated by sendmail in the
+ 4.8 How can I check my to ensure that it's re-writing
addresses correctly?
+ 4.9 What is procmail, and where can I get it?
+ 4.10 How can I solve "cannot alias non-local names" errors?
+ 4.11 Is sendmail Year 2000 (Y2K) compliant?
+ 4.12 How can I batch remote mail to be sent using my ISP while
delivering local mail immediately?
+ 4.13 What does "unknown mailer error 1" mean?
+ 4.14 How do I queue mail for another domain?
+ 4.15 How do I create attachments with sendmail?
+ 4.16 How do I find sendmail's version number?
+ 4.17 How do I handle user names with upper-case characters?
+ 4.18 What does "NOQUEUE: Null connection from ..." mean?
+ 4.19 How do I configure sendmail for POP/IMAP/... ?
+ 4.20 How can I automatically copy messages based on sender or
recipient addresses?
+ 4.21 How can I send mail to all users?
+ 4.22 Why can't I receive external mail?
+ 4.23 How do I restrict attachments with sendmail?
+ 4.24 Can I get sendmail to verify an entire e-mail address instead
of just the domain?


+ 5.1 Sun Microsystems SunOS/Solaris 1.x/2.x

o 5.1.1 How can I solve "line 273: replacement $3 out of bounds"
o 5.1.2 How can I solve "line 445: bad ruleset 96 (50 max)" errors?
o 5.1.3 Why does version 8 sendmail (< 8.7.5) sometimes hang
under Solaris 2.5?
o 5.1.4 Why can't I use SunOS/Solaris to get email to certain
large sites?
o 5.1.5 Why do I have trouble compiling on Solaris?
o 5.1.6 How does 8.X compare to 8.X+Sun?

+ 5.2 IBM AIX

o 5.2.1 The system resource controller always reports sendmail
as "inoperative". What's wrong?
o 5.2.2 Why can't I use AIX to get email to some sites?
o 5.2.3 Why can't I get sendmail 8.7.1 to use MX records with
AIX 3.2.5?

+ 5.3 Linux

o 5.3.1 Red Hat

· Why do I have so many sendmail problems after
configuring sendmail with linuxconf?
· I built from and it works
until the next reboot of the machine. What is
going on?
· Why can't I receive mail with Red Hat 7.1 and later?

o 5.3.2 SuSE

· Where is the file on SuSE Linux?

* 6. ADDITIONAL INFORMATION SOURCES (RFC 1807 bibliography format)

+ 6.1 Reference material devoted exclusively to sendmail
+ 6.2 Reference material with chapters or sections on sendmail
+ 6.3 Reference material on subjects related to sendmail
+ 6.4 World-wide web index pages on sendmail
+ 6.5 World-wide web index pages Internet email in general
+ 6.6 Online tutorials for sendmail
+ 6.7 Online archives of mailing lists and Usenet newsgroups,
relating to Internet email

* 7. THANKS!
-- John