I have spent many years studying security: both the theory and how to put it into practice.
Security in programming
Even a humble contact form, if written badly, can bring your server to its knees and cause untold headaches if spammers exploit it.
I recognise that your website and server are incredibly valuable to you, and will never compromise on the security of the code I write for you. Whilst working on a site, if I spot a problem in existing code I will inform you immediately, along with various options as to how to fix or mitigate the issue.
Networking & network security
I can advise on all aspects of network security, from Firewalls and Intrusion Detection to how best to harden a unix machine (Linux/*BSD/Mac OS X) against attack.
I have many years of experience in networking: I am Cisco qualified (my CCNA score was 950/1000) and I have had a lot of training on PIX, ASA and IPS equipment. As with programming, no job is too small: I can help with anything from making small changes on existing routers to setting up a firewall to consulting on any aspect of a network setup.