The 5 Principles of IT Customer Service Success

Page # Correction
68 It’s Maxwell Maltz, not Malcolm Maltz.

The Compassionate Geek:  Mastering Customer Service for IT Professionals

Page # Correction
71 First paragraph should say “Work with a partner…”

Cisco ASA for Accidental Administrators: An Illustrated, Stpe-by-Step Cisco ASA Learning and Configuration Guide

10/31/15: I was just made aware of an embarrassing error in the table of contents in which the page numbers are off by 18 pages. In other words, for example, the page which is listed in the table of contents as page 23 is actually page 5. This is being corrected in edition 1.1. You can download a corrected Table of Contents here.

The Accidental Administrator: Cisco ASA Security Appliance, Second Edition

The current edition is 2.1, which incorporates the following corrections and updates.  Click here for edition 2.1 errata.

Page # Correction
25 Step 10: In the last sentence in the description, it should read “…we’ll use the password [email protected]” for consistency with the exercise step.
35 Step 2: Formatting error. The words “interface vlan1” should be bolded.
36 Step 6: The prompt on the second bullet should be “ciscoasa(config)#”
41 Step 1: Obviously, you’re probably not in a seminar.
53 Step 1: This isn’t an error as much as an update. I’m now recommending the use of either tftpd32 or tftpd64 instead of the Solar Winds TFTP server. There’s nothing wrong with the Solar Winds product, but they make you register to download it. The tftpd32 and tftpd64 products are excellent, they don’t require registration, and they include syslogd and some other features. Download both the 32 and 64-bit versions at
68 In step 4b, after entering the IP address of your ASA’s inside interface, push the radio button labeled Telnet
75 Cisco Secure Access Control Server has been discontinued and replaced by Cisco Secure Access Control System.
95 Step 5: This command continues at the top of page 96. The actual command is:

no aaa authentication ssh console LOCAL

96 Step 6: To clarify, you should attempt to log in using SSH
113 In the Diffie-Hellman Group section, the last sentence should read, “Group 1 is 768 bits, group 2 is 1024 bits, and group 5 is 1536 bits.”
128 I have updated the information on Remote Access VPN configuration with a new tutorial on RADIUS at I have also created several new videos on various ways to authenticate VPN users, including RADIUS, Kerberos, and LDAP on my video channel at
154 Step 45 is no longer necessary.  See an updated configuration, including a video, here.
155 Steps 50 and 51 are not necessary, since the DMZ sits behind a lower security level (50) than the Inside network (100).  See an updated configuration, including a video, here.
164 In the second paragraph, second sentence, it should read, “The appliance has a single IP address and the inside and outside interfaces are on the same subnets.”
166 Step 8: For clarification, you can use a network or a host address here. If you choose to assign a network address, it must be the same network as where your management workstation is located. If you choose to assign an individual host address, it must be the address of your management workstation. (If you’re not clear on the difference between network and host addresses, spend some time reading TCP/IP tutorials or watching YouTube videos on IP fundamentals.)

The Accidental Administrator: Cisco ASA Security Appliance, Edition 2.1

Page # Correction
68 In step 4b, after entering the IP address of your ASA’s inside interface, push the radio button labeled Telnet
116 Eliminate the parenthetical comment. It is irrelevant.
151 Insert an additional step (step 20a) just before step 21. Step 20a: Launch the Adaptive Security Device Manager, either in a browser window or by using the ASDM launcher, depending on how you installed it.
163 This is not a correction, but an update for anyone using ASA software version 8.4 or later. Cisco modified the steps for configuring transparent mode on appliances running software version 8.4 and later. I created a blog post here and a video here, both covering the updated steps.
164 In the second paragraph, second sentence, it should read, “The appliance has a single IP address and the inside and outside interfaces are on the same subnets.”

The Accidental Administrator: Cisco Router Step-by-Step Configuration Guide, 1st Edition, Versions 1 and 1.1

Page # Correction
57 Press Enter after typing reload.
63 Step three: After entering the command ip address dhcp, press the Enter key. Then type the command no shutdown and press the Enter key.
65 Exercise 1.4 is numbered incorrectly. It should be Exercise 1.5.
68 or in Kindle, location 1002 or 1422, depending on your reader. Exercise 1.5 should be numbered 1.6.

Step four: The correct command is show startup-config, not show running-config.

70 Step 10: This command must be executed in Privileged EXEC (enable) mode.

Step 15: This command must executed in Global Configuration (config t) mode.

84 This isn’t a correction, but I thought this information might be helpful. The maximum # of hosts supported on each of the old classful network is determined by taking 2 to the power of “n” minus 2. The formula for determining the total number of available hosts on a class A network is 224-2 which equals 16,777,214, for a class B network, it’s 216-2 which equals 65,534, and for a class C network, it’s 28-2 which equals 254.
88 Figure 51 is wrong.  The subnet mask in binary should be 11111111.11111111.11111111.11000000, as shown in this corrected graphic:

Cisco tutorial | learn to subnet

191 This is additional information that you should know about RIPv2 and EIGRP.

The No Auto-Summary Command Allows Routers to Advertise Subnets
Both RIPv2 and EIGRP, by default, enable automatic summarization along classful network boundaries. In other words, if a router is connected to both the and subnets, automatic summarization will force it to only advertise the major network of If you want the router to advertise subnets, you must use the router configuration mode command “no auto-summary”. Many network administrators make a habit of disabling automatic summarization, but it really depends entirely on whether you want subnets advertised or summarized.
232 Diagram 7 has two typos in it. The Managers subnet ID should be and the Sales subnet ID should be
233 In the solution, the first configuration line should read:

– router(config)#access-list 10 deny 0.0.255

236 Diagram 8 has a typo on Router02’s interface configuration. The second interface in the list should be labeled G0/1, not G0/0.
243 Diagram 9 has the same typos in it as Diagram 7 on page 232. The Managers subnet ID should be and the Sales subnet ID should be

In the soltuion, directly below the diagram, the first configuration line should read as follows:

– router01(config)#access-list 101 deny ip host eq 23

257 Step six: The steps must be performed in Global Configuration Mode. That’s probably obvious, but just in case…
303 Very early editions of the book (those with a “TM” by the title instead of a ®) included instruction and a graphic indicating that you should use the command ip access-group BlockRouter03 in to apply an IPv6 access-list.  The correct command is ipv6 traffic-filter BlockRouter03 in.  The correct graphic is shown here:

Cisco tutorial | ipv6 access-list

309 Also, in very early editions of the book, RFC 2460 was inadvertantly omitted from the list of recommended RFCs for more information about IPv6.

The Accidental Administrator: Linux Server Step-by-Step Configuration Guide

Page # Correction
50 Students frequently ask what “grep” stands for. One of the most common definitions I’ve found is “global regular expression parser”.
51 Step 2: In the description, it should read “…in the demo3 directory:”

Step 5: the command should include the “n” optiion. It should look like this:

grep -Hrn “I grok Linux” /demo (the “H” tells it to print the filename for each match, the “r” tells it to act recursively, reading all files under each directory, and the “n” tells it to print line numbers.

65 Damn autocorrect! In steps 1 and 3, it should be two dashes before “help”, like this:

chmod –help

ls –help

111 Step 5: A word of explanation: “ro” means read only, “sync” tells NFS to reply to requests only after the changes have been committed to stable storage such as a disk drive.
114 Step 4: Again, autocorrect thought it knew what I meant. There are two dashes before “list”. Also, if you just want to see the runlevels where a particular daemon starts, you can append the name to the end of the command like this:

chkconfig –list nfs

131 Step 7: The description should read “…present disk usage with the quotacheck command:”

Step 10: You must specify the directory name following the command, like this:

repquota /home

146 Step 23: After removing the directives, save and exit the file with the :wq command.
160 An additional note regarding sudo, passwords are cached. If you need to clear the cache, use the command “sudo -K”
161 In the last paragraph, it should read “…copies the file “file1” from the directory “common”…” (Removing the file extension .txt.)
168, 169 Exercise numbers are messed up. Here’s the correct numbering:

Student Exercise 16.7: Finding Superuser User Accounts

Student Exercise 16.8: Checking User Account Logon History

Student Exercise 16.9: Linux Root Password Recovery

172 In the secion, “How to use the “ps” command”:” remove the dash before aux, so it should look like this:

ps aux

181 This isn’t errata, but I left out a great site for learning how to build Linux configs. Check out (Okay, maybe it is an error, since I should have never left it out!)

Tweeting Linux:  140 Linux Configuration Commands Explained in 140 Characters or Less

Page # Correction
88 The graphic in figure 37.1 is incorrect.  It is an inadvertant duplicate of the graphic for 36.1.
244 The two graphics are reversed.  Figure 112.2 should be 112.3 and vice versa.
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