Recently, we needed to check if any computers inside of a given network were configured to use OpenDNS servers. In our case, the router (10.10.100.1) is acting as a DNS cache and configured to query upstream DNS servers. What we want to do is first catch any internal IP address using OpenDNS IP addresses (208.67.222.222 …
Tag: DNS
Oct 31
Mikrotik DNS Failover Script
Traditionally, a minimum of two DNS servers are used for any given computer for redundancy. The problem is that Windows computers (and others) will choose the fastest responding server and ignore the order given (primary, secondary, etc.). If we wish to force a primary and only fail over to a secondary, then scripting coupled with …
Oct 19
Dnsmasq on CentOS 6 for Filtering
DNS filtering is a quick and easy method to block access to certain websites. It can be used to block third party advertisements within websites, block known malware infected sites, and can even be used as a content filter (pornography, etc.). In this post, we’ll walk through setting up Dnsmasq on CentOS 6. Dnsmasq is a …