I'm not in forensics myself - i'm a network administrator; so take my advice as you see fit!
If your a dev at the moment, then I would say that there is rather a lot of changes in direction needed to be made.
I'd start with the basics of networking, maybe something like CompTIA Network+. Then other items such as Security+.
They are only basics though and just the starting point.
Worth looking into how networks operate, followed by how attacks are performed.
Most attacks in general are performed against Windows - so I'll look into how the OS performes and operates in a detailed level. From IIS through to Active Directory. I would also take a look at Windows backoffice system as there are many exploits there - such as SQL and Exchange.
I don't really use Linux much, mainly due to preference rather than anything else - but a lot of forensics are done on *nix based O/S's - so that maybe something else to look into as well.
However I still think the first steps would be networking. Network+ for fundementals, and then maybe some cisco courseware would be a good starting point. Security+ is quite basic but does cover a wide spectrum. (as well as being OS independant)
Firewall configuration on major devices such as CheckPoint, WatchGuard, Cisco, FortiGate etc.
On a Windows OS level then items such as the networking structures, logging, and general network operations (such as AD etc.) Bare in mind that most security issues are from internal users - and as most companies use Windows it maybe the best area. (And don't forget to check out the history of Windows. A copy of Windows95 is truly shocking compared to Windows XP SP2!)
I always look at security from the view of the attacker - rather than the administrator. Tools from sites like
are great.
Most of the above is general security rather than forensics - however I'd initally say that the difference would be a very indepth knowledge of operating systems and firewalls - in terms of locating logs. Then I would assume that knowledge of networking would be essential for the logs along with information on the operating system. (So Cisco and Windows would be the key ones in my opinon - although it depends what your market niche will be. E.G. Large corporates will be using Cisco stuff, whilst SME will be using Linksys or similar)
Hope this is of some help!
Cheers, and good luck.
Steve.
"They have the internet on computers now!" - Homer Simpson