Simple Web Application Firewall (WAF) CloudFormation Template

A Web Application Firewall (WAF), is a layer of protection you can add to your web application. Adding a WAF to an Application Load Balancer (ALB) is pretty straightforward. You need to create at least one WebACL, to which you configure some rules (that filter the traffic), you can then attach the WebACL to the […]

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check_http Gives 403 Forbidden Error Monitoring Site via AWS Application Load Balancer (ALB)

We’ve started to host websites on AWS, we want to monitor using NagiosXI, but we got some odd results when first attempting to. The web application has no “index.html” page, which is one cause of the 403 forbidden error. However we were getting the same thing even when specifying the correct path. It turns out […]

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Installing a Specific Ruby Version

We needed to install Ruby 2.7 instead of what normally comes with Ubuntu 20.04 LTS, if we installed a later than 2.7 Ruby version, the particular application (i.e. Staytus in this case) would barf. The nice people at BrightBox have created some packaged installs of Ruby at various versions.https://www.brightbox.com/docs/ruby/ubuntu/#adding-the-repositoryhttps://launchpad.net/~brightbox/+archive/ruby-ng (Latest version supported 20.04) We first […]

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Microsoft Exchange 2016 – How to Fix Exchange DAG Witness Failed State

In certain situations the Exchange DAG witness can become a problem, this can occur during an upgrade or can happen if there is a network interruption. Although the DAG will continue to operate the witness is considered failed, which can cause odd behaviour in a failover scenario, as there is no quorum available for the […]

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