What does DSmailhost$?m.$m$ mean in sendmail?
After looking through 21.6 Macro Conditionals: $?, $|, and $. in sendmail, 3rd Edition, I believe this line means the following:
- If $m (subdomain name) is defined, replace the value with .$m$.
$ sendmail -d0.1 < /dev/null ... =========== SYSTEM IDENTITY (after readcf) ============ (short domain name) $w = host canonical domain name) $j = host.example.com (subdomain name) $m = example.com (node name) $k = host ========================================================
- Since $m is defined as example.com, the S macro (SMART_HOST) is replaced with mailhost.example.com.
- If $m was not defined, the S macro (SMART_HOST) would be mailhost