For the past 15 years I have worked as a Network and Systems admin for ISPs and Telcos using UNIX, Linux, and other vendor specific gear like Cisco and Juniper.
I am certified in top-class security and systems admin certifications: CCNP (Security), CISSP, Certified Ethical Hacker, LPIC (for Linux), plus other network certifications.
Besides just securing what you've requested, I will throw in an additional penetration test process just to prove that what I implemented works, and identify other loopholes which we can fix.