Server security audit and hardening

We run a production Linux server that carries our business, and we want an experienced system administrator to audit its security and raise it to a solid, defensible baseline. The server has grown over time, and we are honest that some settings were made quickly and never revisited. We need a fresh pair of expert eyes to tell us where we actually stand, what the real risks are, and what to fix first, in plain language we can act on.

The work should cover the essentials of hardening end to end. We expect a review of the operating system and package updates, a tightened firewall with only the ports we truly need, and a careful pass over access: who can log in, how, with what keys, and whether anything should be revoked. We want secure remote access, sensible service configuration, and logging that would actually let us reconstruct events. Where you find weak passwords, stale accounts or over-broad permissions, we want them flagged and corrected with our sign-off.

Just as important as the fixes is a short, practical incident response plan: what to watch, how we would know something is wrong, and the concrete steps to take if the server is compromised. Please describe your audit method, the checklist you follow, how you will document findings by priority, and how you will verify that each change holds without breaking the services we depend on.