netstat command and shell pipe feature can be used to dig out more information about particular IP address connection. You can find out total established connections, closing connection, SYN and FIN bits and much more. You can also display summary statistics for each protocol using netstat. This is useful to find out if your server […]
Category: TCP/IP
Text-only “What is my IP Address”
Text-only “whatismyip” address? checkip.dyndns.com
Get your external IP address – TEXT ONLY
There are a lot of useful services online where you can quickly and easily get your external IP address, however they are almost all laden with a bunch of other crap, like ads and stuff. For a clean, simple text only view of your external IP address go to https://secure.internode.on.net/webtools/showmyip?textonly=1 I created a shortened URL. […]
DenyHosts: Remove / Delete an IP address
How do I remove my own home IP address from DenyHosts?Simply removing your IP from /etc/hosts.deny does not work since DenyHosts keeps track of the attempts in the /usr/share/denyhosts/data directory. In order to remove your IP address you will need to do the following. Step # 1: Stop DenyHosts # /etc/init.d/denyhosts stop Step # 2: […]
Linux Change MTU Size
How do I change MTU size under Linux? You need support in both network hardware and card in order to use JumboFrames. If you want to transfer large amounts of data at gigabit speeds, increasing the default MTU size can provide significant performance gains. Changing the MTU size with ifconfig command In order to change […]
Detecting listening network ports on Linux
It is importand to check for ports that are open and there are not needed. For a list of network ports that are open you can use the following commands: netstat -tulp orlsof -i -n | egrep ‘COMMAND|LISTEN|UDP’ Or, you are not limited to netstat or lsof but you can always use a port scanner, […]
Linux Kernel /etc/sysctl.conf Security Hardening
How do I set advanced security options of the TCP/IP stack and virtual memory to improve security and performance of my system? How do I configure Linux kernel to prevent certain kinds of attacks using /etc/sysctl.conf? How do I set Linux kernel parameters? sysctl is an interface that allows you to make changes to a […]