I'm following the mailman guide but cannot locate /etc/postfix/:

root@dur:~# ll /etc/postfix/
total 124
drwxr-xr-x   3 root root  4096 Aug 27 20:04 ./
drwxr-xr-x 170 root root 12288 Aug 27 19:58 ../
-rw-r--r--   1 root root   373 Aug 14 01:44 dynamicmaps.cf
-rw-r--r--   1 root root  2252 Aug 27 20:04 main.cf
-rw-r--r--   1 root root  1280 Aug 16 23:59 main.cf.1.orig
-rw-r--r--   1 root root  3298 Aug 25 16:59 main.cf.2.mysql
-rw-r--r--   1 root root  1323 Aug 26 00:38 main.cf.3.dovecot
-rw-r--r--   1 root root  2092 Aug 27 20:01 main.cf.4
-rw-r--r--   1 root root  5563 Aug 14 01:43 master.cf
-rw-r--r--   1 root root   150 Aug 17 00:21 mysql_alias.cf
-rw-r--r--   1 root root   150 Aug 17 00:22 mysql_domains.cf
-rw-r--r--   1 root root   150 Aug 17 00:21 mysql_mailbox.cf
-rw-r--r--   1 root root 19707 Apr 13 13:33 postfix-files
-rwxr-xr-x   1 root root  8729 Oct  6  2011 postfix-script*
-rwxr-xr-x   1 root root 26498 Apr 13 13:33 post-install*
drwxr-xr-x   2 root root  4096 Apr 13 13:33 sasl/
root@dur:~#