While Ubuntu is generally a very stable and secure platform, it's important to be prepared for when problems occur and that you know how to deal with them. In this chapter, we discussed common troubleshooting we can perform when our servers stop behaving themselves. We started off by evaluating the problem space, which gives us an understanding of how many users or servers are affected by the issue. Then, we looked into Ubuntu's log files, which are a treasure trove of information we can use to pinpoint issues and narrow down the problem. We also covered several networking issues that can come up, such as issues with DHCP, DNS, and routing.
In our final chapter, we'll take a look at preventing problems from occurring in the first place and recovering from disasters that manage to sneak through anyway. While it's impossible to prevent every problem that can possibly occur, it's critical that we understand how to make our servers as resilient as we possibly can. We'll take a look at...