Sendmail
Sendmail is a general purpose internetwork email routing facility that supports many kinds of mail-transfer and -delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet.
Send Mail Via Mailertable
If you want to send email for a particular domain direct to a server rather than using the default smart host you can use the mailertable.
cd /etc/mail nano mailertable otherdomain.com smtp:mailserver.otherdomain.com makemap hash mailertable < mailertable nano sendmail.mc FEATURE(`mailertable') make -C /etc/mail service sendmail restart
Send Message Via Command Line
cat test.msg
To: me@domain.com Subject: sendmail test From: me@domain.com This is a test email message.
sendmail -vt < test.msg
Vacation
vacation -i nano ~/.vacation.msg
From: James Smith <james@domain.co.uk> Subject: Out Of Office (Re: $SUBJECT) Thank you for your email. I am now on holiday. Regards, James
nano ~/.forward
\jsmith, "|/usr/bin/vacation -a james -a james.smith -r1d jsmith"
Generate SMTP AUTH Username Password
perl -MMIME::Base64 -e 'print encode_base64("username\0username\0mypassword");'
Flush The Mail Queue
/usr/lib/sendmail -v -q -C/etc/mail/sendmail.cf
Set A Catchall Account
/etc/mail/virtusertable
@yourdomain.com user
Then, rebuild the hash and restart sendmail...
makemap hash virtusertable < virtusertable newaliases /etc/init.d/sendmail restart
Set Different SMTP Port
/etc/mail/sendmail.mc
define(`RELAY_MAILER_ARGS', `IPC $h 525')
Set Maximum Message Size
/etc/mail/sendmail.mc
define(`confMAX_MESSAGE_SIZE', `10485760')
Change Root User Sender/From Email Address
See Do Not Expose Root section below as well...
/etc/mail/sendmail.mc
FEATURE(`genericstable',`hash -o /etc/mail/genericstable.db') GENERICS_DOMAIN_FILE(`/etc/mail/generics-domains')
/etc/mail/generics-domains
server1.domain.co.uk domain.co.uk
/etc/mail/genericstable
root server1@domain.co.uk
cd /etc/mail/ makemap hash genericstable < genericstable m4 sendmail.mc > sendmail.cf /etc/init.d/sendmail restart
Do Not Expose Root
nano /usr/share/sendmail-cf/domain/generic.m4
dnl EXPOSED_USER(`root')
What Features Is Sendmail Compiled With?
sendmail -d0.1
ERROR: mailx sendmail bfcommit permission denied
chown root /var/spool/mqueue
alias List - Editing: How To
In this example there is an alias entitled 'staff'...
- log in via ssh to server
- su - root
- screen -r
- nano /etc/mail/aliases
- [page down]
- find staff: line
- edit as needed
- save
- newaliases
- CTRL+A D
- logout
ERROR: sendmail[14870]: gethostbyaddr(192.168.1.1) failed: 1
Add entries in your DNS or /etc/hosts (or both!) for this ip address.
Add A Custom Macro Definition File
cd /usr/share/sendmail-cf/domain cp -av generic.m4 mydomain.co.uk.m4
Find All Dovecot Sieve Out of Office Links
find /home/ -maxdepth 2 -type l -name '.dovecot.sieve' -print |sort
Find All Email Forward Files
find /home/ -maxdepth 2 -type f -name '.forward'
and to see them...
find /home/ -maxdepth 2 -type f -name '.forward' -printf "\n%p\n" -exec cat {} \;
Example Forward File With Copy Left On Server
me@anotheremail.com \me
Edit The Custom Macro Definition File
Remove the line to expose root, otherwise emergency emails will not be accepted by ISP.
EXPOSED_USER(`root') <-- delete this line
Typical Server Macro File
divert(-1) divert(0) include(`/usr/share/sendmail-cf/m4/cf.m4') VERSIONID(`$Id: sendmail-procmail.mc 2010-10-28 plittlefield Exp $') OSTYPE(linux) DOMAIN(mydomain.co.uk) DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1,Name=MTA') DAEMON_OPTIONS(`Port=smtp,Addr=192.168.0.200,Name=MTA') define(`ALIAS_FILE', `/etc/mail/aliases') define(`STATUS_FILE',`/etc/mail/statistics') define(`SMART_HOST',`[smtp.myisp.co.uk]') FEATURE(`authinfo',`hash -o /etc/mail/authinfo.db') FEATURE(`access_db') FEATURE(`genericstable') FEATURE(`relay_entire_domain') FEATURE(`accept_unresolvable_domains') FEATURE(`smrsh',`/usr/sbin/smrsh') FEATURE(`local_lmtp',`/usr/sbin/mail.local') FEATURE(`local_procmail') FEATURE(`no_default_msa') FEATURE(`limited_masquerade') FEATURE(`masquerade_envelope') MASQUERADE_AS(`mydomain.co.uk') MASQUERADE_DOMAIN(`server1.mydomain.co.uk') EXPOSED_USER(`root') MAILER(local) MAILER(smtp) MAILER(procmail)
Multiple SMTP Smart Hosts
Add colon separated server hostnames and update your authinfo file.
define(`SMART_HOST',`[smtp.company1.com]:[auth.smtp.company2.co.uk]')
ERROR: sm-mta SYSERR(root): collect: Cannot write
Fix: change the ownership of /var/spool/mqueue to root.
chown root /var/spool/mqueue
Using Telnet To Test SMTP With Authentication
echo -ne '\000username\000password' | openssl base64
or
perl -MMIME::Base64 -e 'print encode_base64("username\0username\0password");'
OR generate your AUTH PLAIN encrypted string using the gen-auth command from the web site link below.
Choose PLAIN and then your username and password.
./gen-auth
Now log in via telnet...
telnet smtp.company.co.uk smtp Trying 212.227.15.163... Connected to smtp.company.co.uk. Escape character is '^]'. 220 smtp.company.co.uk Welcome to our SMTP server EHLO test 250-smtp.company.co.uk 250-STARTTLS 250-AUTH LOGIN PLAIN 250-AUTH=LOGIN PLAIN 250-SIZE 120000000 250 HELP AUTH PLAIN cGF1bGx5AHTHISISFAKEeQBjaDRybDNz 235 2.7.0 Authentication successful MAIL FROM:<me@company.co.uk> 250 2.1.0 Ok RCPT TO:<info@company.co.uk> 250 2.1.5 Ok data 354 End data with <CR><LF>.<CR><LF> Message. . 250 2.0.0 Ok: queued as CB3361DE15F4 quit 221 2.0.0 Bye Connection closed by foreign host.
http://www.jetmore.org/john/code/gen-auth
http://www.freebsdwiki.net/index.php/SMTP,_testing_via_Telnet
http://qmail.jms1.net/test-auth.shtml
http://www.commandlinefu.com/commands/view/2857/create-auth-plain-string-to-test-smtp-auth-session
