Re: Parsing Syslog and Acting on it, using other input too

[Shawn Wilson <ag4ve.us () gmail com>]

Christopher Morrow <morrowc.lists () gmail com> wrote:
> On Thu, Aug 29, 2013 at 10:50 AM, Don Wilder <don.wilder () gmail com>
> wrote:
> > I wrote a script in Linux that watches for unauthorized login
> attempts and
> > adds the ip address to the blocked list in my firewall. You might
> want to
> > search sourceforge for a DYN Firewall and modify it from there.
>
> because fail2ban was too hard to install? or because you just wanted
> to test yourself?

Actually I did the same. I use ipset lists (generally with a timeout) and take a regex or two and black / white list 
from a YAML file and just take (possibly multiple inputs) from piping tail -F. I also store addresses for future 
reference (by the script or otherwise). 

This is quite maintainable as I can look at a list of people who have attacked the mail server and compare it to web 
attacks. Each process is a different type of service (different config file) and probably a different ipset. Due to 
ipset not actually doing anything until I make an iptables rule for it, I can run my script in a test mode (by default) 
and just see what happens (check it's logs and the ipset list it generates). I haven't found the need for this yet but 
I can use cymru to look up how big their net is (see geocidr for an example of how to do this in perl) and use a 
hash:net ipset type and cover a whole net.

Basically what I'm saying in doing it this way is quite expandable and isn't very hard and I can do tons of stuff that 
fail2ban can't (I don't think - it's been a while since I looked).