I recently updated my SSL keys. Several servers are accessed by keys from a few devices. A common authorized_hosts file was created as a template. This post covers the generation and use of SSL keys.
Category: System Administration
Posts related to system administration. Mostly applicable to Linux distributions, mostly Ubuntu/Debian and OpenWrt; see tags.
HTTP2 on Apache2
HTTP2 allows web servers to serve multiple content streams on the same connection. This can reduce server and network load. I have updated my Ubuntu Apache servers to enable HTTP2. After installing the latest Ubuntu release, I needed to redo the switch to the event Multi-Processing Module (MPM) and switch PHP content delivery back to… Continue reading HTTP2 on Apache2
Banner message for ssh
Using a pre-authentication banner with ssh can verify identification before a password is entered. This can help prevent leaking passwords. Banners are simple to configure but often disabled in the default configuration.
Securing Content with Headers
There are a number of methods to attach a web site and its viewers’ browsers. Many of these have simple fixes that can be applied in the Apache configuration file. This article presents some of the headers that can be applied
fail2ban non-root startup
fail2ban runs as root by default. This is unnecessary for its functionality, other than to alter firewall rules. The firewall rules can be safely done, using sudo to enable the required calls. The Debian/Ubuntu init.d file has provisions to start fail2ban as a non-root user, but newer releases use systemd to start and stop the process. This requires a different procedure. This procedure is for my servers which use Shorewall to maintain the firewall.
WordPress SSH2 configuration
Instead of the packaged WordPress I run the version provided by WordPress. It is installed using a different userid from the userid the webserver runs as. To enable updates from the Admin Dashboard, I enabled sftp (ssh). This is how I did it.
init.d for Non-root Processes
When installing third-party applications, they often default to running as root. The server applications for TeamSite/LiveSite are among those. I have applied a simple modification to the init.d scripts that start them as a non-root user. It also allows the scripts to be run by members of an administration group via sudo. This approach applies… Continue reading init.d for Non-root Processes
Geo blocking with tcpwrappers
I recently had an issue with frequent login attempts against one of my services. These were almost all from countries that should not be accessing my service. To resolve the issue I implemented geo-blocking with TCP Wrappers. This is how I went about geo-blocking connections.
Shell Scriptlets
This post will be continually developed. I recently designed some solutions to solve some issues with init.d and setup scripts. These may be of use to others, and I will likely reuse them.
Securing TLS
A StackExchange question on using HAProxy’s capture feature to pass data from TCP mode to HTTP mode prompted me to update my SSL configuration. This was intended to get an A+ rating from SSL Labs by sending non-SNI capable clients to a server with weaker ciphers. This was to enable clients on WinXP/IE8, Java 6,… Continue reading Securing TLS