Networking security and monitoring on the cheap
Building a complex network scheme requires a lot of knowledge and experience. It also requires a bit of insight and guesswork into what can and should be used. Trying to do all this without budget is even worse. You basically don't have any chance to do it correctly.
Or do you....
See, part of the problem is not knowing the tools are there in the first place. And because the Internet is big into open source, you've got plenty of options once you become aware of what they are. So that's what I'm going to try to deal with here. Trying to build a defensible architecture based off spending the least amount of money as possible. Saving the money on these tools allows you to spend that money else where. Like in good firewall.
Love them or hate them, here's my recommendations.
Network monitoring - Paessler PRTG
Log Management - GrayLog
SIEM - OSSIM
Firewall - Palo Alto
Patch Management - WSUS
Now, before I get yelled at...
1) I don't deal with much of a web presence, so I don't have to fight with Web Application Firewalls. I mostly deal with brick and mortar. If you've got a web front end to deal with, I can't really help you.
2) Palo Alto is expensive. But it is awesome. Money spent there is well worth the spend.
3) PRTG is only free for 100 sensors. 100 is better than 0, which is probably what you are monitoring now. And running a ping here and there is not monitoring. Don't even pretend.
Sure, many of these platforms are free. But you will spend a lot of time in sweat equity. Don't expect an easy time with setup and tuning. Expect to spend a lot of time beating your head on the wall, trying to figure something out.
The other part of this is do what everyone says to do, but no one does: document.
Documentation is the untold glue that holds all these train wrecks together. Spend a lot more time documenting than you think you should. Because that first time you have to rewrite a script to get your Graylog server to accept traffic on the correct port, you'll wish you had. Because you'll forget about that script, and reboot. And because you didn't write it down, you'll have to figure it out again. No fun.
Or when your Graylog setup script gets overwritten due to an upgrade. Fun times. Fun times.
