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Configuration·LPIC-2

SSH hardening, and who has been trying

SSH is the one service on every machine, which makes it the one worth hardening properly. This guide reads what sshd is actually running with - including drop-in files that override the main config - compares both families, and checks the authentication logs for the failed attempts an internet-facing host collects continuously.

202: System Security Guide 14 of 29 Intermediate

Both servers. Every command reads configuration or logs; nothing is changed and sshd is never restarted.
Server NameIP AddressOSRolesCPURAMHDD
LPIC2-A01192.168.0.78Ubuntu 26.04 LTSPrimary service host - BIND, Apache, Samba, Postfix. Topic 204 RAID runs on loop devices; this machine has no spare disk2 Core4 GB50 GB
LPIC2-B01192.168.0.79AlmaLinux 10.2Second service host - nginx, NFS, DNS secondary, and the other family's spelling of each service2 Core4 GB50 GB

This guide includes

Use this because SSH is the one service on every machine. This matters because a setting can come from a drop-in that is read before the main file - so the file you edited may not be the one in force.

Before you start

  1. The effective configuration, not the file

  2. Drop-ins, which are read before the main file

  3. Who has been trying

Official sources