We have already discussed packet analysis with tcpdump but will dive deeper in this post! Tcpdump is probably the most popular and capable tool that allows you to dig down to all the bits and bytes of network traffic, including TCP flags. Ngrep, stands for “network grep,” and like its cousin, the…
Let’s consider the following scenario: you have a Linux host that has more than one network interface, both are routable and both are up and running. How do you determine which interface or route is used when trying to reach another host? In other words the routing table looks like…
Most of medium to large companies have three levels of escalation of trouble tickets: Help Desk – The first level is generally handed by the help desk (or service desk) that receives and processes user reported outages via phone or other communication means. Before opening and escalating a ticket to…
Every network interface is set with an MTU (Maximum Transmission Unit) value that defines the byte size of the largest protocol data unit that is allowed to pass. So what happens when a frame or packet is larger in size than the MTU value of the interface? It depends on whether…
Troubleshooting Remote Application Issues How many times are users aware of remote application issues before you are? How much time do you spend collecting information about the problem from the end users or your monitoring systems before you can pinpoint the root cause? The number of hardware and software components…