In QA we look for risk and run constant calculations about what we should focus on next. Using the IETF's specification for RFC 1149, (aka "A Standard for the Transmission of IP Datagrams on Avian Carriers," dated 1 April 1990) I'll go over how to identify the risks in a system and where to focus your attention first as a tester. I'll hit highlights of stuff that commonly goes wrong and give you some tools to find out where your risks are. Please read RFC 1149 beforehand (takes less than 5 minutes): https://tools.ietf.org/html/rfc1149