Setting correct MTU for OpenVPN

VPN connections can be sensitive to incorrect/low MTU set within your network, or on networks between you and your server. It is important that the correct MTU is set, to ensure fast and error-free VPN performance. Symptoms of incorrect MTU Slow VPN performance Incomplete page load of resources via HTTP over VPN (ie. PHPMyAdmin, Munin, … Continue reading

Understanding cache flow when using PageSpeed and Varnish

On MageStack, when you change a file, it changes immediately. There are no disk caches, no PHP caches or file caches of any kind. If you create, or modify a file, the change is reflected immediately. So if you change a CSS file, and view that file in via SSH/FTP, you'll see the change straight … Continue reading

Troubleshooting HAProxy

If you see the following message We've detected too many requests coming from your IP address and as a result you have been temporarily blocked until your traffic subsides. Please try again within the next few minutes. It is likely you have triggered the DOS (denial of service) rule. This can happen if your multiple … Continue reading

Troubleshooting OpenVPN

If you cannot connect to the OpenVPN and are receiving the following error TLS Error: TLS key negotiation failed to occur within 60 seconds” Please see for a resolution If you can connect but cannot ping any hosts on the internal network and are using Windows Vista or above, please disable IPv6 on the … Continue reading

Troubleshooting Varnish/HAProxy/Nginx

Given there are 3 reverse proxies, if one is causing an issue, finding the cause can sometimes be difficult. Testing Nginx This can be tested by overwriting the IP address for the domain in your hosts file to be (regardless of the domain name) This will put the traffic directly to Nginx on the … Continue reading