How to set a MAC address on a Cisco 3700 router.

This command in interface configuration mode will change the MAC address for a specific interface on the router. R1(config-if)#mac-address DE.AD.BE And this is what I get when I use the show run command and view the properties of the interface. interface FastEthernet0/0 mac-address 00de.00ad.00be ip address ip nat inside ip nat enable ip […]

How to get comprehensive SSL information out of a website with Ubuntu.

The sslscan utility will print out a comprehensive report listing all of the SSL ciphers used by a website secured by SSL. This can be very useful information when you are planning to attack this website. Or just for research purposes. In this example, I am scanning and getting information about the ssl ciphers […]

How to create keys with easy-rsa without a password prompt.

To create a new set of keys for OpenVPN using Easy-RSA, we firstly need to clean our environment and get ready for the build. $ ./easyrsa init-pki Now we need to build the certificate authority. $ ./easyrsa build-ca nopass   Note: using Easy-RSA configuration from: ./vars Generating a 2048 bit RSA private key ………..+++ ………………………………………+++ […]

Cisco access control lists I have worked out.

These Cisco ACL`s are to block ICMP ping requests from a certain IP address. I developed these experimenting with GNS3. I had two Cisco 3750 routers in GNS3 and I added static IP addresses. for the R1 router and for R2. I then added the ACL lists to R1 and ran the write-memory […]

Add a fancy progress bar to the apt command on Linux.

To add a fancy progress bar to the apt command on Linux, edit this file: /etc/apt/apt.conf.d/99progressbar and add the line below. Dpkg::Progress-Fancy "1"; Save the file and when you next install software with the apt command, you will get a fancy progress bar at the bottom of the screen. This is a very nice addition […]

Get information about your computer hardware with Linux.

This command will print the make and model of your motherboard. jason@eyjafjallajkull:~$ sudo dmidecode -t baseboard [sudo] password for jason: # dmidecode 2.12 SMBIOS 2.4 present.   Handle 0x0002, DMI type 2, 8 bytes Base Board Information Manufacturer: Gigabyte Technology Co., Ltd. Product Name: H55-USB3 Version: x.x Serial Number: To get information about your network […]

A simple C code snippet that shows how to do a function call.

This simple C code snippet shows how to do a function call in C. This calls the hi() function and runs it in main(). Very simple but useful code. And this does not need to call any include files. As I am using the built-in write() function. int hi() { int i; i = 0; […]

Useful subnetting cheat sheet. This will help when subnetting.

This is a very useful subnetting chart that will help out a student of Cisco networking. This shows how many subnets you can have with a certain subnet mask. This can be tricky to learn and something like this will really help out. Another way to calculate subnetting is with the sipcalc command for Linux. […]

Change your MAC address on Linux with the command line.

To change your MAC address in Linux, you just need to issue these few commands, and then re-run dhcp or reconfigure the interface. This works for both wired and wireless cards. Bring down the interface. jason@eyjafjallajkull:~$ sudo ifconfig eth0 down [sudo] password for jason: Set a new MAC address on the interface. jason@eyjafjallajkull:~$ sudo ifconfig […]

Just upgraded my Ubuntu 15.04 installation to kernel 4.0.

I have just upgraded my Linux installation to kernel 4.0. This new kernel brings me many benefits. One of those is that the radeon drivers finally work and I no longer need to install the kernel source and try and compile the ATI drivers that you download from the Internet. I just load up my […]

Adding an IP address to the management interface for a Cisco switch.

Adding an IP address to the management interface of a Cisco switch allows connection over an Ethernet connection to manage the switch configuration. Firstly, switch to privileged exec mode. tyrion>en tyrion# Then enter the configure terminal command to configure terminal settings. tyrion#configure terminal Now we are configuring settings for vlan 99. tyrion(config)#interface vlan 99 Now […]

List all of your IP addresses using the ip command.

The ip command will list all of your ip addresses when combined with the grep command to look for all inet words. This is a very useful one-liner. ubuntu ~/Documents $ ip a | grep "inet " inet scope host lo inet brd scope global eth0 inet peer scope global […]

How to login as root on Ubuntu. Enable the root account.

The root account on an Ubuntu machine is normally disabled. This is how to enable the root account to use this Linux account like a traditional Linux system. Firstly, enable the root account by setting a new password. ubuntu ~ $ sudo passwd root Enter new UNIX password: Retype new UNIX password: passwd: password updated […]

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New QOS device for smoother network throughput when gaming and using Youtube.

The new QOSIMODO device allows a network to run much more smoothly even with online gaming or Youtube/Netflix running. Prioritizing certain traffic will improve the quality of your online gaming experience, and a hardware device that helps with this would be a boon to a gamer that shares a network with other people. More games […]