Bash script commands not working in cron

Question

I have the following bash script to read logs and check for brute force then block violating IP using iptables.

#!/bin/bash
#blah blah run some commands to get the IP
iptables -A INPUT -s $p -j REJECT --reject-with icmp-host-prohibited
echo "BANNED $p FOR $COUNT ATTEMPTS" |wall

I did chmod 755. When I run the command from terminal it works fine. But when I setup a cronjob using crontab -e as root, it gets the IP and echos the "BANNED ..." message to the wall but nothing is added to the iptables list.

PS. I tried both #!/bin/bash and #!/bin/sh but no luck.

why do you need to add iptables rules in cron, if you want to add iptables rulesand you want them to be persistent you can add them to /etc/sysconfig/iptables or rc.local — Saddam Abu Ghaida
– Saddam Abu Ghaida, Commented Apr 10, 2014 at 9:45
Try adding the full path of all commands. which iptables will give it to you for iptables, do the same for the others. — fedorqui
– fedorqui, Commented Apr 10, 2014 at 9:48

kpopovbg · Accepted Answer · 2014-04-10 09:49:23Z

16

Try to provide full path to iptables e.g.

$ which iptables
/sbin/iptables

and than modify your script like that:\

#!/bin/bash
#blah blah run some commands to get the IP
/sbin/iptables -A INPUT -s $p -j REJECT --reject-with icmp-host-prohibited
echo "BANNED $p FOR $COUNT ATTEMPTS" |wall

answered Apr 10, 2014 at 9:49

kpopovbg

3011 silver badge6 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

MLSC · Accepted Answer · 2014-04-10 09:55:31Z

0

Try the following solution should work for you:

cat cronjob
* * * * * /path/to/script.sh

Then:

chmod +x cronjob
chmod +x script.sh

/etc/init.d/crond start  #redhat based servers like centos
/etc/init.d/cron  start  #debian based servers like ubuntu

crontab cronjob

NOTE: Sometimes you need to enter full path of IPTABLES command if your rules aren't added to /etc/sysconfig/iptables .

edited Apr 10, 2014 at 9:55

answered Apr 10, 2014 at 9:48

MLSC

5,9728 gold badges60 silver badges90 bronze badges

2 Comments

fedorqui Over a year ago

While this is a more general and interesting solution, I don't think it is a problem on cronjob configuration, but on the paths of the scripts.

MLSC Over a year ago

Yes..path of script and path of iptables command maybe is the problem

Collectives™ on Stack Overflow

Bash script commands not working in cron

2 Answers 2

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related