Secure you Debian Server

This guide contain the steps i always do on first time login after installing Debian on a blank server.

• You need root access for the first steps, so gain root access as secure as you possibly can.

Update Debian

This is a good idea to do before anything else.

• Using the -y switch on apt-get will assume "yes" to all questions from apt-get.
• Sometimes ca-certificates needs an upgrade, and to make sure you know this is done you will need to press q to continue the apt-get -y upgrade

root@pulspc:~# apt-get -y update
Ign http://ftp.debian.org jessie InRelease
Get:1 http://ftp.debian.org jessie-updates InRelease [145 kB]
Get:2 http://ftp.debian.org jessie Release.gpg [2,373 B]
Get:3 http://ftp.debian.org jessie Release [148 kB]
Get:4 http://ftp.debian.org jessie-updates/main Sources [15.4 kB]
Get:5 http://ftp.debian.org jessie-updates/main amd64 Packages/DiffIndex [6,916 B]
Get:6 http://security.debian.org jessie/updates InRelease [63.1 kB]
Get:7 http://ftp.debian.org jessie-updates/main Translation-en/DiffIndex [2,704 B]
Get:8 http://ftp.debian.org jessie/main Sources [7,056 kB]
Get:9 http://ftp.debian.org jessie/main amd64 Packages [6,776 kB]
Get:10 http://security.debian.org jessie/updates/main Sources [188 kB]
Get:11 http://ftp.debian.org jessie/main Translation-en [4,582 kB]
Get:12 http://security.debian.org jessie/updates/main amd64 Packages [346 kB]
Get:13 http://ftp.debian.org jessie-updates/main amd64 2016-11-07-2025.04.pdiff [531 B]
Get:14 http://ftp.debian.org jessie-updates/main amd64 2016-11-30-2028.41.pdiff [530 B]
Get:15 http://ftp.debian.org jessie-updates/main amd64 2016-11-30-2028.41.pdiff [530 B]
Get:16 http://security.debian.org jessie/updates/main Translation-en [183 kB]
Fetched 19.5 MB in 7s (2,674 kB/s)
Reading package lists... Done

root@pulspc:~#apt-get -y upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
  apt apt-utils base-files bash bind9-host ca-certificates dbus dnsutils e2fslibs e2fsprogs exim4 exim4-base exim4-config
  exim4-daemon-light file host libapt-inst1.5 libapt-pkg4.12 libbind9-90 libc-bin libc-dev-bin libc6 libc6-dev libc6-i386
  libcairo2 libcomerr2 libcurl3-gnutls libdbus-1-3 libdns-export100 libdns100 libevent-2.0-5 libfcgi-perl libgnutls-deb0-28
  libgnutls-openssl27 libhogweed2 libicu52 libio-socket-ssl-perl libirs-export91 libisc-export95 libisc95 libisccc90
  libisccfg-export90 libisccfg90 libjasper1 liblcms2-2 liblwres90 libmagic1 libnettle4 libpam-modules libpam-modules-bin
  libpam-runtime libpam-systemd libpam0g libpng12-0 libss2 libssl-dev libssl-doc libssl1.0.0 libsystemd0 libtiff5 libudev1
  libxml2 linux-image-3.16.0-4-amd64 linux-libc-dev locales multiarch-support openssl python-pil sed systemd systemd-sysv
  tzdata udev vim vim-common vim-runtime vim-tiny w3m
78 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/87.2 MB of archives.
After this operation, 391 kB of additional disk space will be used.
Reading changelogs... 67%

........ Lots of lines removed for convienience !!

Setting up openssl (1.0.1t-1+deb8u6) ...
Setting up ca-certificates (20141019+deb8u2) ...
/usr/sbin/update-ca-certificates: [--verbose] [--fresh]
Setting up libfcgi-perl (0.77-1+deb8u1) ...
Setting up libio-socket-ssl-perl (2.002-2+deb8u2) ...
Setting up python-pil:amd64 (2.6.1-2+deb8u3) ...
Processing triggers for libc-bin (2.19-18+deb8u7) ...
Processing triggers for ca-certificates (20141019+deb8u2) ...
Updating certificates in /etc/ssl/certs... 10 added, 10 removed; done.
Running hooks in /etc/ca-certificates/update.d....done.
root@pulspc:~#

Make SSH Access more secure

Brute force SSH Login Protection

Inspiration was found at http://www.linode.com/docs/security/securing-your-server/