server

Setting up your first firewall via SSH

Ok, now you have just acquired your first remote server, and you are about to configure its firewall via SSH. This is an important step that you must get right if you don't want to find yourself locked out of the server with no possibility to restore your remote access.

Introduction

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Web server

Tutorials

General tutorials found elsewhere on the web.

Linux Internet Web Server and Domain Configuration Tutorial @ yolinux.

Firewall

All Linux servers use iptables as a firewall. However, there is a choice of front ends to help the administrator set up the appropriate rules.

Firewall

Generic firewall documentation:

Firewall @ ubuntu documentation:
https://help.ubuntu.com/community/Firewall

Firewall and Proxy Server HOWTO (dated: 2000!)
http://tldp.org/HOWTO/Firewall-HOWTO.html

Advanced topics

Detecting and deceiving network scans
http://jengelh.medozas.de/documents/Chaostables.pdf

Towards the perfect ruleset
http://jengelh.medozas.de/documents/Perfect_Ruleset.pdf

Troubleshooting bind9

Logs

Unless set up otherwise with the command logging (see official documentation), bind9's error messages are directed to the default error logs (/var/logs/syslog).

The server does not respond

$ dig @mynameserver.example.com mywebsite.example.com

; <<>> DiG 9.7.3 <<>> @mynameserver.example.com mywebsite.example.com
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached

It could be one of three things:

1) The nameserver (bind9) is not started. Check: