Guides on the net suggest that you do not edit sendmail.cf by hand. First, make changes to sendmail.mc then rebuild sendmail.cf using the command: "m4 sendmail.mc > sendmail.cf". However, this command sometimes fails and before you know it you have unknowingly made changes to sendmail.cf -- the file is now 0 bytes. The error message is below:
[root@host mail]# m4 sendmail.mc > sendmail.cf sendmail.mc:10: m4: cannot open `/usr/share/sendmail-cf/m4/cf.m4': No such file or directory
Things are pretty simple if you look at the error.. but it is very deceiving. Take a look at your sendmail.cf.
Ooppss.. sendmail.cf is now zero bytes. You can rebuild sendmail.cf from sendmail.mc using m4, but you just executed the exact command to re-generate sendmail.cf ending in errors. Re-starting sendmail will make things worse. Sendmail will still work as it read sendmail.cf before the error. Restarting it will re-read the zeroed out sendmail.cf file.[root@host mail]# ls -la sendmail.cf -rw-r--r-- 1 root root 0 Feb 18 10:02 sendmail.cf
I got stuck in this error before. And a colleague got stuck in it just recently.
The guides either forgot to mention that or assumed that it is installed and you will need to have installed the sendmail-cf rpm. How do you know that sendmail-cf is the required rpm? Take a closer look at the first few lines of sendmail.mc.
[root@host mail]# head sendmail.mc divert(-1)dnl dnl # dnl # This is the sendmail macro config file for m4. If you make changes to dnl # /etc/mail/sendmail.mc, you will need to regenerate the dnl # /etc/mail/sendmail.cf file by confirming that the sendmail-cf package is dnl # installed and then performing a dnl # dnl # make -C /etc/mail dnl #
So what you can do now is install sendmail-cf rpm.
[root@host mail]# yum -y install sendmail-cf Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: mirror.web.com.ph * extras: mirror.web.com.ph * updates: mirror.web.com.ph Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package sendmail-cf.x86_64 0:8.13.8-8.1.el5_7 set to be updated --> Finished Dependency Resolution Dependencies Resolved ================================================================================ Package Arch Version Repository Size ================================================================================ Installing: sendmail-cf x86_64 8.13.8-8.1.el5_7 updates 306 k Transaction Summary ================================================================================ Install 1 Package(s) Upgrade 0 Package(s) Total download size: 306 k Downloading Packages: sendmail-cf-8.13.8-8.1.el5_7.x86_64.rpm | 306 kB 00:00 Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction Installing : sendmail-cf 1/1 Installed: sendmail-cf.x86_64 0:8.13.8-8.1.el5_7 Complete!
Now re-run "m4 sendmail.mc > sendmail.cf" and it will be error free. You can safely make changes to sendmail.mc and generate sendmail.cf from that.
