This command will set a passphrase for the server pem file for OpenVPN on Linux. I setup a VPN configuration on Ubuntu and forgot to set the passphrase. This is how I managed to set one. ubuntu@ip-172-31-13-140:~$ sudo openssl rsa -des3 -in server-key.pem -out server2.pem Enter pass phrase for server-key.pem: writing RSA key Enter PEM … Read more
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.BER1(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 192.168.0.1 255.255.255.0 ip nat inside ip nat enable … Read more
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 facebook.com and getting information about the ssl ciphers … Read more
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$ ./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 … Read more
Useful CISCO Access Control Lists 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. 192.168.0.1 for the R1 router and 192.168.0.32 for R2. I then added the ACL lists to … Read more
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";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 … Read more
Get information about installed hardware with these commands 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 … Read more
Do a simple function call in C. This code snippet shows how to do this 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 … Read more
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. … Read more
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:jason@eyjafjallajkull:~$ sudo ifconfig eth0 down [sudo] password for jason: Set a new … Read more
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 … Read more
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#tyrion>en tyrion# Then enter the configure terminal command to configure terminal settings. tyrion#configure terminaltyrion#configure terminal Now we are configuring settings for vlan 99. tyrion(config)#interface vlan … Read more
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 127.0.0.1/8 scope host lo inet 172.31.20.16/20 brd 172.31.31.255 scope global eth0 inet 10.8.0.1 peer 10.8.0.2/32 scope global … Read more
