rkhunter … doesn’t support redhat ES 4 (nahant update 3)?

actually, it does. but version 1.28 (the latest version as of this writing) doesn’t recognize it.
if you’re running rkhunter and get the following message:
Determining OS… Unknown
Warning: This operating system is not fully supported!
Warning: Cannot find md5_not_known
All MD5 checks will be skipped!

you can get rkhunter to acknowledge your OS by doing the following:
# cd usr/local/rkhunter/lib/rkhunter/db
# pico os.dat

(i’m still a fan of vi, but i’m trying to be tolerant) 🙂
in this file, look for like 189. add this line immediately below as such:
190:Red Hat Enterprise Linux ES release 4 (Nahant Update 3):/usr/bin/md5sum:/bin
save the file and then run rkhunter -c once again.
no errors!

a bash script to delete files older than 7 days.

i would like to share this nifty little script, courtesy of a forum post on linuxquestions.org, one of the most authoritative websites on linux genius and learning.

find /directoryname -type f -mtime +7 -exec rm {} \;

this script will find all the files that are older than 7 days (as indicated by mtime +7 in the /directoryname folder (note: it is advisable to use an absolute path here) and execute the rm command, which will delete (or “remove”) the files.

smtp settings and sendmail.

i forgot to mention that i had one element missing from my nagios setup (besides check_mysql, which i still think someone needs to write a better version of): i haven’t had sendmail running on my linux server in about two years, ever since i learned that optonline.net blocks port 25 (and i liked using my own server for outbound email).
today, i decided to change that all, except i didn’t know what settings to use. i was fortunate enough to stumble upon this very cool list of smtp servers and my sendmail.cf file was updated in no time.
for some reason, i still needed sendmail-cf, so i simply ran:
# yum install sendmail-cf
on my fedora core 5 box, and when i ran
# make -C /etc/mail
everything started running perfectly. i already received my backlog of nagios emails that were queued since i installed the software, so i know everything is running smoothly.