Typically when I need to use tshark I do so on a Linux server however there are times where it is convenient to have tshark available on my Windows 7 laptop. The TShark application is installed with Wireshark so installing TShark is very easy using the Wireshark GUI intsaller on Windows. One thing that makes tshark more useful is adding the tshark.exe executable to your PATH on Windows so you can open a command prompt and use TShark from any directory. Follow the directions below to first install Wireshark and then to add the directory that includes tshark.exe to your Windows 7 PATH.
You can install telnet on Windows 7 by following the directions in this article however you may want to instead install telnet using cygwin. The cygwin application provides you Linux type environment in Windows and you can use the cygwin installer to install lots of different Linux applications. One application that you might want to install is telnet however if you search for telnet via the cygwin installer there won’t be any results provided. Below is information on how to install telnet using cygwin on Windows.
Postfix Error: cannot update mailbox /var/mail/root for user root. cannot create file exclusively: No such file or directory
While working on a project unrelated to Postfix on a CentOS server I noticed an error in the mail logs that indicated an issue with the root users mailbox. I have yet to locate the root cause of the problem however I was able to resolve the problem easily. Below I explain the error in more detail as well as how I was able to resolve the problem with sending email to the root users inbox.
While working on the computer shop network I had to modify the configuration on our switch which is a Cisco Catalyst 2950. After making a bunch of changes I was testing things to make sure all was working as expected however after taking a break and logging back into the 2950 it appeared that all of the changes made had been reverted. I was assuming the Catalyst 2950 had lost power briefly which means all of the changes were lost since they had not been saved to the startup config yet. To verify my assumption I needed to look at the amount of time the switch had been up however “uptime” is not a valid iOS command. Below is information on the command used to verify uptime on a Cisco Catalyst 2950.
A couple days ago I was working on the network at the computer shop and ran into an issue configuring the Cisco Catalyst 2950 switch we have on part of the network. The goal was to set up three VLAN’s to segregate traffic on three segments of the network that each have their own purpose. One of the VLAN’s is used by the employees, one VLAN used for the public, and the third VLAN used to host servers that provide various services. I was in a rush to minimize downtime when I was configuring the access to the 2950 switch itself and attempted to assign an IP address to two of the VLAN’s. Below I explain the details of the issue that caused as well as an explanation of why this won’t work.