There are many different firewall options out there, but one of the most prevalent seems to be the Cisco ASA. This post is a basic configuration outline of the general setup of an ASA firewall that has basic connectivity, as well as dynamic and static NAT functions. While there are many different services an ASA can provide, this post centers on an ASA configuration running on the 8.x code version doing only basic functions. This particular setup is on a firewall in routed mode, that is used for NAT/PAT with only an inside and outside interface setup.
The first config settings to enter on an ASA, or most any other Cisco networking devices is the hostname of the device, domain name, and the enable password for logging into privileged exec mode.
enable password Secret1 Continue reading Basic Cisco ASA firewall setup →
Why bother with tftp?
Many network devices such as Cisco routers and switches use
tftp in order to download their IOS config updates.
tftp can also be used for network based installs or for booting up diskless systems. Knowing how to setup a
tftp server comes in quite handy when circumstances like these arise.
Getting started . . .
The Network Topology
Let’s say we’re dealing with a private network– 192.168.100.0/24. We’ll designate our
tftp server and
tftp test client as 192.168.100.5 and 192.168.100.105 respectively. You will need
superuser privileges on both your server and client in order to successfully perform all of these commands.
Get the Necessary Packages
Log on to 192.168.100.5 and download the necessary programs; make sure they survive reboots:
# yum install tftp-server xinetd
# chkconfig tftp on Continue reading How to Setup a TFTP Server Under CentOS/RHEL 6 →
For people running older versions of Solaris, like 8/9, the firewall of choice to install was
ipfilter. Now, with Solaris 10 it has become the default, built-in with the OS. I wanted to do a short post about adding configuration settings for ipv6 and plan to cover ipv4 in detail in a later post.
One thing to note is that
ipfilter must run it’s ipv6 rules under a separate file. In Solaris 10, the default location for the filter rules is in
/etc/ipf and the firewall rules are located in the files
ipf6.conf for ipv4 and ipv6 respectfully. Here is a sample of the current file on one of my servers,
# IPv6 Filter rules to be loaded during startup
# See ipf(4) manpage for more information on
# IP Filter rules syntax. Continue reading ipfilter and ipv6 →
The Cisco archive command has been around for several years now and is still valid for smaller operations that are unable to afford or require a commercial software package to do the same thing. Two of the main benefits include backing-up your configurations after changes and logging the commands that were executed by each user. The commands necessary to accomplish these tasks are fairly straightforward,
sw1# config t
sw1(config-archive)# path ftp://192.168.100.50/configs/sw1
sw1(config-archive)# log config
sw1(config-archive-log-config)# logging enable Continue reading Cisco archive command →
Although we have seen examples of how to install
gpg for Windows and integrate with Outlook, this class lab is designed to get
gpg working in Linux with the Evolution email client.
Generate a Key for signing only
# gpg --gen-key
Please select what kind of key you want:
(1) RSA and RSA (default)
(2) DSA and Elgamal
(3) DSA (sign only)
(4) RSA (sign only)
Your selection? 1
What keysize do you want? (4096) Continue reading GPG Lab →
This is a listing of the current books that have found their way onto my desk for reading, reviewing or acting as a paperweight,
Linchpin: Are You Indispensable? by Seth Godin
Routing TCP/IP, Volume 1, 2nd Edition by Jeff Doyle, Jennifer Carroll
TCP/IP Illustrated, Volume 1: The Protocols, 2nd Edition by Richard Stevens
RHCSA/RHCE Red Hat Linux Certification Study Guide by Michael Jang
TcL Scripting for Cisco IOS by Raymond Blair, Arvind Durai, John Lautmann