TechPain

df error - 'df: cannot read table of mounted file systems'

2011-07-26T12:09:00.000-07:00



[root@host]# df -h

df: cannot read table of mounted file systems

[root@host]# cat etc/mtab

(nothing)

[root@host]# lvdisplay

  Parse error at byte 6 (line 1): unexpected token

This is often related to a disk space issue. A post from insanelabs.com recommended freeing up space and then rebuilding /etc/mtab from /proc/mounts like so:



[root@host]# grep -v rootfs /proc/mounts > /etc/mtab

Seemed to do the trick, df is now returning expected results.

ODBC logon scripts - ODBCCONF

2011-07-06T14:35:00.000-07:00

ODBCCONF is deprecated, and "should not be used", but I couldn't find a better way to do this in the time that I had.
I needed a logon script to create some data sources (ODBC's) so I used ODBCCONF in a batch file that looked like this:

ODBCCONF CONFIGDSN "SQL Server" "DSN=DataSourceName| Description=| SERVER=DBhostnameorIP| Database=DB_name| Trusted_Connection=yes"

This breaks down as follows:
ODBCCONF - The utility to run
CONFIGDSN - Configures a User DSN (CONFIGSYSDSN would be for a System DSN)
"SQL Server" - The driver to use
DSN= Data source name
Description= A description of the DSN
SERVER= DB host or IP address
Database= DB name
Trusted_Connection=yes (Use Windows NT authentication)

Windows: Show or Delete files older than X days

2011-05-27T14:18:00.000-07:00

Using forfiles to show and/or delete files older than X amount of days:

/p = path
/s = subdirectories (recursive)
/m = mask
/d = days
/c = cmd to be run

Show .log files in C:\LogFiles (recursively) older than 1 year:



forfiles /p C:\LogFiles /s /m *.log /d -365 /c "cmd /c echo @file is at least 1 year old."

Remove .log files in C:\LogFiles (recursively) older than 1 year:



forfiles /p C:\LogFiles /s /m *.log /d -365 /c "cmd /c del @file"

Save as a .bat and schedule it.

Domain Controller Troubleshooting with DCDIAG , REPADMIN , and NETDIAG

2011-05-24T15:22:00.000-07:00

DCDIAG

DCDIAG analyzes the state of domain controllers in a forest or enterprise and reports any problems to help in troubleshooting.

Details available at MS TechNet.

Example: dcdiag.exe /V /D /C /E > c:\dcdiag.log

REPADMIN

Repadmin.exe is a Microsoft Windows 2000 Resource Kit tool that is available in the Support Tools folder on the Windows 2000 CD-ROM. It is a command-line interface to Active Directory replication. This tool provides a powerful interface into the inner workings of Active Directory replication, and is useful for troubleshooting Active Directory replication problems.

Example: repadmin.exe /showrepl dc* /verbose /all /intersite > c:\repl.txt

Details available at MS TechNet.

NETDIAG

This command-line diagnostic tool helps to isolate networking and connectivity problems by performing a series of tests to determine the state of your network client. These tests and the key network status information they expose give network administrators and support personnel a more direct means of identifying and isolating network problems. Moreover, because this tool does not require parameters or switches to be specified, support personnel and network administrators can focus on analyzing the output rather than on training users how to use the tool.

Example (to be run on each DC): netdiag.exe /v > c:\netdiag.log

Details available at MS TechNet.

Win Server 2008 DC RADIUS server for a Cisco ASA VPN

2011-05-02T20:12:00.000-07:00

Thanks to FixingIT.wordpress.com. I pulled most of this post from there, made some tweaks, and added the Cisco CLI as an alternative to ASDM.

The following steps are a walk through of configuring a Windows 2008 Server Domain Controller as a RADIUS server for an ASA, and configuring that ASA as the RADIUS client. This will allow VPN users to authenticate against Active Directory instead of locally on the ASA.

These steps assume the following:

Windows Server 2008: 192.168.0.10
Cisco ASA: 192.168.0.5

Configure the ASA

CLI

The applicable parts of the config are as follows:



interface Vlan1

nameif inside

security-level 100

ip address 192.168.0.5 255.255.255.0 



aaa-server SERVER protocol radius

accounting-mode simultaneous

aaa-server SERVER host 192.168.0.10

key mysecretkey

radius-common-pw mysecretkey

ASDM

Create an IP Name object for the target

Under the Firewall section, expand the Objects link and select the IP Names.
Click the Add button at the top.
Enter a descriptive name, the IP address of the DC/RADIUS server and a description of the server.
Click OK and then Apply

Create a new AAA Server Group

Click the Remote Access VPN section.
Expand AAA Setup and select AAA Server Groups.
Click the Add button to the right of the AAA Server Groups section.
Give the server group a name, like TEST-AD, and make sure the RADIUS protocol is selected.
Accept the default for the other settings. And click OK

Add the RADIUS server to the Server Group.

Select the server group created in the step above.
Click the Add button to the right of Servers in the Select Group.
Under the Interface Name select the interface on the ASA that will have access to the RADIUS server, most likely inside.
Under Server Name or IP Address enter the IP Name you created for the RADIUS server above.
Skip to the Server Secret Key field and create a complex password. Make sure you document this as it is required when configuring the RADIUS server. Re-enter the secret in the Common Password field.
Leave the rest of the settings at the defaults and click Ok.

Configuring the Windows 2008 DC/RADIUS Server

*requires domain admin privileges
Add the Network Policy Server function.

Connect to the Windows Server 2008 server and launch Server Manager.
Click the Roles object and then click the Add Roles link on the right.
Click Next on the Before You Begin page.
Select the Network Policy and Access Services role and click Next.
Under Role Service select only the Network Policy Server service and click Next.
Click Install.

After the role finishes installing you will need to set up the server using the Network Policy Server (NPS) management tool found under Administrative Tools.

Registering the server.
After launching the NPS tool right-click on the entry NPS(Local) and click the Register Server in Active Directory. Follow the default prompts.

Create a RADIUS client entry for the ASA.

Expand the RADIUS Clients and Servers folder.
Right-click on RADIUS Clients and select New RADIUS Client.
Create a Friendly Name for the ASA device. I used “CiscoASA” but if you had more than one you might want to make it more unique and identifiable. Make sure you document the Friendly Name used as it will be used later in some of the policies created.
Enter the Server Secret Key specified on during the ASA configuration in the Shared secret and Confirm shared secret field.
Leave the default values for the other settings and click OK. See Figure 1 for all the complete RADIUS Client properties.

Create a Connection Request Policy

Expand the Policies folder.
Right-click on the Connection Request Policies and click New.
Set the Policy Nameto something meaningful. I used CiscoASA because this policy is geared specifically for that RADIUS client. Leave the Type of network access server as Unspecified and click Next.
Under Conditions click Add. Scroll down and select the Client Friendly Name condition and click Add
Specify the friendly name that you used when creating the RADIUS Client above. Click OK and Next.
On the next two pages leave the default settings and click Next.
Under the Specify a Realm Name select the Attribute option on the left. From the drop down menu next to Attribute: on the right select User-Name. Click Next again.
Review the settings on the next page and click Finish.

Create a Network Policy.

Right-click the Network Policy folder and click New.
Set the Policy Name to something meaningful. Leave the Type of network access server as Unspecified and click Next.
Under Conditions click Add.
Add a UsersGroup condition to limit access to a specific AD user group. You can use a generic group like Domain Users or create a group specifically to restrict access.
Add a Client Friendly Name condition and again specify the Friendly Name you used for your RADIUS client.
Click Next. Leave Access granted selected and click Next again.
(Important Step) On the authentication methods leave the default selection and add Unencrypted authentication (PAP, SPAP).
Accept the default Constraints and click Next.
Accept the default Radius Settings and click Next. Review the settings and click Finish.

Restart the Network Policy Server service. Probably not be necessary, but not a bad idea.

Test Your RADIUS Authentication

CLI

test-fw# test aaa authentication SERVER host 192.168.0.10 username testuser password mypassword
INFO: Attempting Authentication test to IP address <192.168.0.10> (timeout: 12 seconds)
INFO: Authentication Successful

ASDM

The ASDM utility includes functionality to test RADIUS Authentication.

If necessary re-launch the ASDM utility.
Return to Configuration > Remote Access VPN > AAA Setup > AAA Server Groups.
Select the new Server Group you created.
From the Servers in the Selected Group section highlight the server you created. Click the Test button on the right.
Select the Authentication radio button. Enter the Username and Password of a user that meets the conditions specified in the Network Policy created above then click OK.
If everything works as designed you should see something similar to "Authentication test to host is successful"

Bash Scripting repetitive tasks

2011-03-21T16:55:00.000-07:00

An audit on a Linux server made it necessary to get information regarding every user on the machine, and match those users to a mail directory (which may or may not have a different name). Instead of running the 'finger' command three hundred times and copying the output somewhere I used this:



#! /bin/sh

while read username; do

finger ${username}

done < inputfile > outputfile

exit 0

I saved this as finger_script.sh and copied each of the usernames to the file 'inputfile'. The 'inputfile' contained just the usernames that I cut and pasted from the mail directory in question, and looked like this:



bill     frank     keith     user01    user05    user09

carl     gary      larry     user02    user06    user10

dan      heather   mary      user03    user07    user11

denise   joe       nancy     user04    user08    user12

Running finger_script.sh ran the finger command on each user in the 'inputfile' and immediately output a list of users that did not exist. It also created 'outputfile', which contained a list of the information on each user:



Login: bill                             Name: Bill Person

Directory: /home/b/bill                 Shell: /bin/nologon

Never logged in.

No mail.

No Plan.



Login: carl                             Name: Carl Guy

Directory: /users/carl                  Shell: /bin/nologon

Never logged in.

No mail.

No Plan.



Login: dan                              Name: Dan Theman

Directory: /users/dan                   Shell: /bin/nologon

Never logged in.

No mail.

No Plan.

Fail2Ban - Reload banned IP's after a restart

2011-03-21T16:34:00.000-07:00

Restarting fail2ban will drop all of your currently banned IP's from iptables. To reload those banned IP's try this.

First, output your currently fail2-banned IP's to a text file with the iptables commands:
iptables-save | grep '\-A fail2ban' | sed 's/\-A/iptables\ \-A/' > bannedIPs.txt

Stop fail2ban, make your config changes, etc. and restart:

service fail2ban stop

service fail2ban start

Load your iptables commands by piping your saved rules to bash:
cat bannedIPs.txt | /bin/bash

Broken yum - yum hangs when trying to remove a package

2011-03-17T20:32:00.000-07:00

I removed a package with yum "successfully" but was unable to reinstall it, as yum seemed to think it was already installed.

Check a package for corruption: rpm -Vv package

Remove a package from the rpm database:
rpm -e --justdb --nodeps package

Probably a good idea to yum clean all if you didn't already.

Symlinks - Changing a symbolic link

2011-03-03T11:33:00.000-08:00

$ ln -s new current_tmp && mv -Tf current_tmp current

From Tom Moertel's Blog (Thanks Tom!):

...if I have a symlink current that points to a directory old, and I want to change it to point to a directory new, I might use the following command:

$ ln -snf new current

Strace shows what really happens when I run the command:
$ strace ln -snf new current 2>&1 | grep link unlink("current") = 0 symlink("new", "current") = 0

First, the existing symlink is deleted via the unlink system call. Then a new, identically named symlink is created via the symlink system call. It’s a two-step process, and in between the steps, there is no symlink.

This can be a problem if you expect the symlink to be there always, such as when using the link to point to the active version of a live web site. If you change the symlink while deploying a new version of your site, for example, the web server might try to dereference the link during the small window of time when it doesn’t exist. Oops.

The solution to this problem is to effect the change by creating a new symlink and then renaming it over the old symlink. On Unix-like systems, renaming is an atomic operation, and thus the symlink “change” will be atomic too. By hand, the process looks like this:

$ ln -s new current_tmp && mv -Tf current_tmp current

To remove a symbolic link to a directory you need to rm symlink instead of rm symlink/ because you need to remove the symlink file instead of deleting the directory.

Changing the Remote Desktop (RDP) Listening Port Number

2011-02-21T09:02:00.000-08:00

Changing the port number for RDP (remote desktop protocol) just involves a simple regedit:

1) Start > Search > Regedit

2) Browse to HKEY_LOCAL_MACHINE > System > CurrentControlSet > Control > TerminalServer > WinStations > RDP-Tcp

3) Locate the PortNumber subkey, change it to 'decimal' and change the Port number

4) Adjust firewalls appropriately.

5) Reboot.

Generating and using SSH keys for authentication

2011-02-09T19:13:00.000-08:00

Setting up SSH keys

SSH keys are great, but remember to keep your private key (~/.ssh/id_rsa) safe! And check out the "Top 20 OpenSSH Server Best Security Practices" article at cyberciti.biz for some security tips. All you need to do to use SSH key authentication is to generate a key pair (public and private) and copy the public key to the remote server.

To generate a new key:
ssh-keygen -t rsa

which will look something like this:



[root@localhost ~]# ssh-keygen -t rsa

Generating public/private rsa key pair.

Enter file in which to save the key (/root/.ssh/id_rsa): 

Created directory '/root/.ssh'.

Enter passphrase (empty for no passphrase): 

Enter same passphrase again: 

Your identification has been saved in /root/.ssh/id_rsa.

Your public key has been saved in /root/.ssh/id_rsa.pub.

The key fingerprint is:

xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx root@localhost

This will also create the /.ssh directory with the correct permissions (if it doesn't already exist), along with the private key (id_rsa) and the public key (id_rsa.pub). You can specify different names, which may be useful for creating multiple keys. You can also generate keys for specific users other than root. 'su' is the easiest way to do this, because the directories and permissions won't need to be fixed later:



[root@localhost ~]# su user1

[user1@localhost ~]# ssh-keygen -t rsa

Generating public/private rsa key pair.

Enter file in which to save the key (/home/user1/.ssh/id_rsa): 

Created directory '/home/user1/.ssh'.

Enter passphrase (empty for no passphrase): 

Enter same passphrase again: 

Your identification has been saved in /home/user1/.ssh/id_rsa.

Your public key has been saved in /root/.ssh/id_rsa.pub.

The key fingerprint is:

xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx user1@localhost

The public key will then need to be copied to the remote server's ~user/.ssh/authorized_keys file:
scp .ssh/id_rsa.pub remotehost:.ssh/authorized_keys

Some additional notes on using SSH keys

Verbose output: ssh -vv -l user host

Specify a key to use with the -i flag:
ssh -i /path/to/key -l user host

ssh-keygen flags
Change a passphrase on a key: -p

Specify number of bits: -b 2048

Comment a key: -c comment

Keep a process running after disconnecting SSH session

2011-02-04T21:55:00.000-08:00

nohup: run a command immune to hangups, with output to a non-tty

Run a process in the background (keep it running after SSH session is disconnected):
nohup command &

or

Schedule a command to run later:
echo "command" | at now + 30 minute

Managing a Postfix Queue - Commands

2010-12-31T12:24:00.000-08:00

Show messages in queue: postqueue -p

Display message: postcat /path/to/postqueue/messageID

Delete a message: postsuper -d (queue ID)

Delete ALL messages: postsuper -d ALL

Attempt delivery of a message: postqueue -i (queue ID)

Attempt delivery of all mail queued for a particular site: postqueue -s (site)

Attempt delivery of all messages (flush): postqueue -f

Put mail "on hold" (stop delivery attempts): postsuper -h (queue ID)

Release mail that was put on hold: postsuper -h (queue ID)

Show various postfix queue stats: qshape
More on qshape

Moving SSL Certificates from IIS to Apache

2010-12-17T11:07:00.000-08:00

1) Export the certificate from IIS. The easiest way to do this is from the MMC Certificates snap-in. Instructions for adding the certificates snap-in to MMC are available at technet.microsoft.com

2) Move the .pfx to your Apache web server.

3) Extract the SSL cert and key from the .pfx file:



# To export the private key from the pfx file:

openssl pkcs12 -in win_cert.pfx -nocerts -out key.pem



# To export the certificate from the pfx file:

openssl pkcs12 -in win_cert.pfx -clcerts -nokeys -out cert.pem



# To remove the password from the key:

openssl rsa -in key.pem -out key_with_no_pw.key

4) Install your certificate. Installing certificates is easy!

Adjust Scalix Webmail Attachment Size Limit

2010-09-12T16:21:00.000-07:00

Can I limit the attachment size for messages prepared in Scalix Web Access? Sure.
From the Scalix Wiki:

Scalix 11.x

Navigate to /var/opt/scalix/nn/webmail directory on the Scalix server, where the file swa.properties exists.
Open the swa.properties file with any editor.
Near the top of the file, locate the parameter “maxAttachmentUploadKilobytes”. By default this is set to 10240, which equates to 10MB attachments. Modify the value appropriately and save the file.
Restart scalix-tomcat.

Scalix 10.x

Navigate to /etc/opt/scalix/webmail directory on the Scalix server, where the file partner.xml exists.
Open the partner.xml file with any editor.
Near the top of the file, locate the parameter “maxAttachmentUploadKilobytes”. By default this is set to 10240, which equates to 10MB attachments. Modify the value appropriately and save the file.
Restart Tomcat.

Log Off All Users Except (user x) from Terminal Server - Windows Batch File

2010-09-01T13:37:00.000-07:00

Came across a situation where we needed to automatically disconnect all users from a terminal server, except for one specific user. The following script (thanks Ferdinand!) can be run as a batch file to accomplish just that; it will log off all terminal server users except for 'userx'. It gives each user a 5 minute and 1 minute warning, then runs a 'query session' to see what sessions show up and writes them to a file call 'sessions.txt'. Next it searches the session.txt file for "userx" and writes the rest of the sessions to "killts.txt", logs off those sessions/users, and deletes the .txt files that it created. It goes through the process twice to get active AND disconnected sessions.



@ECHO OFF

msg * You will be logged off in 5 minutes.

choice /T:240 /D N /N > Nul

msg * You will be disconnected in 1 minute! Please log off now!

choice /T:60 /D N /N > Nul

query session >C:\SchedTasks\sessions.txt

find /v "userx" C:\SchedTasks\sessions.txt > C:\SchedTasks\killts.txt

for /f "skip=5 tokens=3," %%i in (C:\SchedTasks\killts.txt) DO logoff %%i

query session >C:\SchedTasks\sessions.txt

find /v "userx" C:\SchedTasks\sessions.txt > C:\SchedTasks\killts.txt

for /f "skip=5 tokens=2," %%i in (C:\SchedTasks\killts.txt) DO reset session %%i

del C:\SchedTasks\sessions.txt

del C:\SchedTasks\killts.txt

EXIT

Here are some other related Windows TS/RDS commands (from thelazyadmin.com):

Query TermServer - Lists all terminal servers in the current domain.
QUERY TERMSERVER [/domain:domain] [/address][/continue]
* /domain:domain - specifies the domain (current logged on domain is default)
* /address - lists the IP address of the terminal server
* /continue - removes the pause between output screens

Query Session - Lists all current sessions running on a terminal server.
QUERY SESSION [sessionname | username | sessionid][/server:servername] [/mode] [/flow] [/connect] [/counter]
* sessionname is the name of the session that you want to query
* username is the name of the user you want to query
* sessionid is the ID of the session you want to query
* /server:servername is the name of the server you are querying
* /mode outputs the current line settings
* /flow outputs the current flow control settings /connect outputs the current connection settings
* /counter outputs the counter information for the server

Query User or Quser - Lists all current users on a terminal server
QUERY USER [username | sessionname | sessionid] [/server:servername]
* sessionname is the name of a specific session that you want to query
* username is the name of the specific user you want to query
* sessionid is the ID of the specific session you want to query
* /server:servername is the name of the server you are querying

Query Process - Lists all processes running on the terminal server.
QUERY PROCESS [ x | processid | username | sessionname | /id:nn | programname] [/server:servername] [/system]
* x lists information on all processes (note - replace x with an asterisk)
* processid lists information about only the specific process ID
* username lists processes running under the context of a specific user
* sessionname lists processes running under the context of a specific session
* /ID:nn lists processes running in the session with the specified session ID number
* programname lists all processes started by the specified executable
* /server:servername is the name of the server you are querying—the default is the server you are logged on to
* /system lists processes running under the system context

TSShutdn - Will shutdown/reboot the terminal server after a specified delay.
TSSHUTDN [wait_time] [/server:servername] [/reboot] [/powerdown] [/delay:logoffdelay] [/v]
* wait_time is the number of seconds to wait after notifying the users that the terminal server is about to shut down before forcibly logging them off (the default is 30 seconds)
* /server:servername is the name of the server to reboot/shutdown (the default is the server to which you are connected)
* /reboot reboots the server
* /powerdown powers down the server after Windows has shutdown; the servers BIOS must support this command
* /delay:logoffdelay the number of seconds to wait after logging out all users before shutting down the system (the default is 30 seconds)
* /v displays verbose information about actions being performed

Logoff - Will logoff the specified user off the terminal server and close the session. Caution, if you don't specify a user it will log you off!
LOGOFF [sessionid | sessionname] [/server:servername] [/v]
* sessionid is the ID of the session you want to logoff
* sessionname is the name of the session you want to logoff
* /server:servername specifies the name of server on which the session you want to logoff is running
* /v displays verbose information about actions being performed

Reset Session - Will kill the specified users session without warning which can be useful when a users session is stuck. Caution, if you don't specify a user it will kill your session!
RESET SESSION [sessionname | sessionid] [/server:servername] [/v]
* sessionid is the ID of the session you want to logoff
* sessionname is the name of the session you want to logoff
* /server:servername specifies the name of server on which the session you want to logoff is running
* /v displays verbose information about actions being performed

MSG - Will popup a message on the specified user(s) terminal server session.
MSG [username | sessionname | sessionid | @filename | x ][/server:servername] [/time:seconds] [/v] [/w] message
* username is the name of the user to whom you are sending the message
* sessionname is the session name to which you want to send the message
* sessionid is the ID number of the session to which you want to send the message
* @filename is the name of a text file containing usernames, sessionnames, or session IDs to which you want to send the message
* x sends the message to all users on the current or specified server (note - replace x with an asterisk)
* /server:servername specifies the server where recipients of the message are connected
* /time:seconds the number of seconds to display the message before the popup closes itself
* /v displays information about the message as it is sent
* /w causes the popup window to wait for the user to click OK before closing message is the text of the message to send

Shadow - Will allow you to shadow or take control of a users session.
SHADOW [sessionname | sessionid] [/server:servername] [/v]
* sessionid is the ID of the session you want to logoff
* sessionname is the name of the session you want to logoff
* /server:servername specifies the name of server on which the session you want to logoff is running
* /v displays verbose information about actions being performed

*** NOTE: Windows Server 2008 changed the name Terminal Services (TS) to Remote Desktop Services (RDS), but the above commands are the same. ***

Bash Scripts with a Variable - Show/Delete Files Older than x Days

2010-08-09T11:10:00.000-07:00

Show files and directories more than 15 days old:
find /path/to/files/* -mtime +15

Delete files more than 15 days old:
find /path/to/files/* -mtime +15 -exec rm {} \;

These can, of course, be scripted (and cron'd, if you set the -mtime flag instead of using a variable). A script to show the files and directories older than x days would look like:



#!/bin/bash --

find /path/to/files/* -mtime $1

And to delete those same files:



#!/bin/bash --

find /path/to/files/* -mtime $1 -exec rm {} \;

Just remember to set the permissions of the script to allow execution, and pass the variable on the command line like so:
# MyScriptName +15

howtogeek.com has a detailed explanation of the command.

Kaspersky Admin Kit - Clients Can't Synchronize

2010-08-05T11:56:00.000-07:00

I beat my head on this one for longer than I'd like to admit... I ran in to a problem where clients would show up in the KAV Admin Kit with the correct ip, the KAV Workstation and Network Agent showed up under 'Applications', and the server could ping the client's IP (and hostname), but the clients would not synchronize. Upon attempting to synchronize I received the all too common 'Cannot synchronize host settings now. Operation will be completed when host becomes available on the network.' error.

The first things I checked were AD and GP, but those both looked good. Firewall settings were correct. I found a thread at the KAV forums that pointed me specifically to the network agent.
Finally I found the problem by browsing to the Kaspersky Admin Kit 'Remote Install' directory:

And then looked at the properties for the Kaspersky Network Agent:

Wrong IP address for the KAV Server! Updated, re-deployed the Network Agent, every snychronized.

Nagios - Customize Nagios Email Notifications

2010-08-03T13:57:00.000-07:00

I finally got tired of getting Nagios notifications and not having all the info I wanted in them. Specifically, I was guessing if the problem had been acknowledged based on the notification interval (how long since I received the last notification), or logging in to Nagios to check.
I decided to customize the Nagios email notifications by editing the # 'host-notify-by-email' command definition, which is the notification type that I've been using.

Before, the # 'host-notify-by-email' command definition looked like this:

command[host-notify-by-email]=/bin/echo -e "***** Nagios *****\n\nHost "$HOSTALIAS$" is $HOSTSTATE$!\n\n$HOSTADDRESS$\n\nDate/Time: $DATETIME$\n" | /bin/mail -s 'Host $HOSTNAME$ is $HOSTSTATE$!' $CONTACTEMAIL$

which produced a notification that simply included the hostname, the state, and the date/time. I hopped on over to the Nagios Macros page at Sourceforge and grabbed what I wanted, then edited the # 'host-notify-by-email' command definition as follows:

# 'host-notify-by-email' command definition

define command{

     command_name    host-notify-by-email

             command_line    /bin/echo -e "***** Nagios *****\n\nThis is a $NOTIFICATIONTYPE$ notice that "$HOSTALIAS$" is $HOSTSTATE$!\n\nHost IP is $HOSTADDRESS$\n\nDuration is $HOSTDURATION$\n\nDate/Time: $LONGDATETIME$\n\nhttp://nagios.mydomain.com/nagios/\n\n\nNagios Summary\nTotal Unhandled Host Problems:$TOTALHOSTPROBLEMSUNHANDLED$\nTotal Unhandled Service Problems:$TOTALSERVICEPROBLEMSUNHANDLED$" | /bin/mail -s 'Host $HOSTNAME$ is $HOSTSTATE$!' $CONTACTEMAIL$

     }

Now my Nagios email notifications look like this:

***** Nagios *****



This is a PROBLEM notice that DevServer is DOWN!



Host IP is 192.168.1.100



Duration is 0d 0h 0m 0s



Date/Time: Tue Aug 3 13:19:25 PDT 2010



http://nagios.mydomain.com/nagios/



Nagios Summary

Total Unhandled Host Problems:1

Total Unhandled Service Problems:0

The "This is a PROBLEM notice" part is created by the $NOTIFICATIONTYPE$ macro. This is nice because it tells you what kind of notification it is ("PROBLEM", "RECOVERY", "ACKNOWLEDGEMENT", "FLAPPINGSTART", "FLAPPINGSTOP", "FLAPPINGDISABLED", "DOWNTIMESTART", "DOWNTIMEEND", or "DOWNTIMECANCELLED"), which is much more useful than just getting another DOWN notice when a problem is acknowledged.

Windows Physical Memory Limits

2010-07-14T08:28:00.000-07:00

Physical Memory Limits: Windows 7
The following table specifies the limits on physical memory for Windows 7.

Version	Limit in 32-bit Windows	Limit in 64-bit Windows
Windows 7 Ultimate	4 GB	192 GB
Windows 7 Enterprise	4 GB	192 GB
Windows 7 Professional	4 GB	192 GB
Windows 7 Home Premium	4 GB	16 GB
Windows 7 Home Basic	4 GB	8 GB
Windows 7 Starter	2 GB	2 GB

Physical Memory Limits: Windows Server 2008 R2
The following table specifies the limits on physical memory for Windows Server 2008 R2. Windows Server 2008 R2 is available only in 64-bit editions.

Version	Limit in 64-bit Windows
Windows Server 2008 R2 Datacenter	2 TB
Windows Server 2008 R2 Enterprise	2 TB
Windows Server 2008 R2 for Itanium-Based Systems	2 TB
Windows Server 2008 R2 Foundation	8 GB
Windows Server 2008 R2 Standard	32 GB
Windows HPC Server 2008 R2	128 GB
Windows Web Server 2008 R2	32 GB

Physical Memory Limits: Windows Server 2008
The following table specifies the limits on physical memory for Windows Server 2008. Limits greater than 4 GB for 32-bit Windows assume that PAE is enabled.

Version	Limit in 32-bit Windows	Limit in 64-bit Windows
Windows Server 2008 Datacenter	64 GB	2 TB
Windows Server 2008 Enterprise	64 GB	2 TB
Windows Server 2008 HPC Edition	Not applicable	128 GB
Windows Server 2008 Standard	4 GB	32 GB
Windows Server 2008 for Itanium-Based Systems	Not applicable	2 TB
Windows Small Business Server 2008	4 GB	32 GB
Windows Web Server 2008	4 GB	32 GB

Physical Memory Limits: Windows Vista
The following table specifies the limits on physical memory for Windows Vista.

Version	Limit in 32-bit Windows	Limit in 64-bit Windows
Windows Vista Ultimate	4 GB	128 GB
Windows Vista Enterprise	4 GB	128 GB
Windows Vista Business	4 GB	128 GB
Windows Vista Home Premium	4 GB	16 GB
Windows Vista Home Basic	4 GB	8 GB
Windows Vista Starter	1 GB	Not applicable

Physical Memory Limits: Windows Home Server
Windows Home Server is available only in a 32-bit edition. The physical memory limit is 4 GB.

Physical Memory Limits: Windows Server 2003
The following table specifies the limits on physical memory for Windows Server 2003. Limits over 4 GB for 32-bit Windows assume that PAE is enabled.

Version	Limit in 32-bit Windows	Limit in 64-bit Windows
Windows Server 2003 with Service Pack 2 (SP2), Datacenter Edition	128 GB 64 GB with 4GT	IA64 2 TB X64 1 TB
Windows Server 2003 with Service Pack 2 (SP2), Enterprise Edition	64 GB	IA64 2 TB X64 1 TB
Windows Storage Server 2003, Enterprise Edition	8 GB	Not applicable
Windows Storage Server 2003	4 GB	Not applicable
Windows Server 2003 R2 Datacenter Edition Windows Server 2003 with Service Pack 1 (SP1), Datacenter Edition	128 GB 16 GB with 4GT	1 TB
Windows Server 2003 R2 Enterprise Edition Windows Server 2003 with Service Pack 1 (SP1), Enterprise Edition	64 GB 16 GB with 4GT	1 TB
Windows Server 2003 R2 Standard Edition Windows Server 2003, Standard Edition SP1 Windows Server 2003, Standard Edition SP2	4 GB	32 GB
Windows Server 2003, Datacenter Edition	128 GB 16 GB with 4GT	512 GB
Windows Server 2003, Enterprise Edition	32 GB 16 GB with 4GT	64 GB
Windows Server 2003, Standard Edition	4 GB	16 GB
Windows Server 2003, Web Edition	2 GB	Not applicable
Windows Small Business Server 2003	4 GB	Not applicable
Windows Compute Cluster Server 2003	Not applicable	32 GB

Physical Memory Limits: Windows XP
The following table specifies the limits on physical memory for Windows XP.

Version	Limit in 32-bit Windows	Limit in 64-bit Windows
Windows XP	4 GB	128 GB
Windows XP Starter Edition	512 MB	Not applicable

Physical Memory Limits: Windows 2000
The following table specifies the limits on physical memory for Windows 2000.

Version	Limit in 32-bit Windows
Windows 2000 Professional	4 GB
Windows 2000 Server	4 GB
Windows 2000 Advanced Server	8 GB
Windows 2000 Datacenter Server	32 GB

Taken from microsoft.com

ESXi Memory Overhead - Can't Admit VM: Memory admission check failed

2010-07-13T16:47:00.000-07:00

Doh. From VM-Help.com:

"On a system with a lower amount of RAM you may find that ESXi allocates too much to run the vmkernel and system services not leaving sufficient memory for running VMs...VM memory overhead includes space for the VM frame buffer and virtualization data structures like shadow page tables...Let's say I have a 1 vCPU VM with 2 GB of memory. ESXi will need a memory overhead of about 137 MB to start the VM. But if I give it 1400 MB memory reservation, then ESXi will need available capacity of about 1537 MB to start the VM. In my case, the VM won't be able to start and will display the error: Can't admit VM: Memory admission check failed. I would need to have an available capacity of more that 1537 MB to start the VM."

Check out VM-Help.com for all the details and screenshots.

Changing the IP Address of a Scalix Server

2010-06-18T14:18:00.000-07:00

Changin the IP of a Scalix server is really easy. Along with changing the obvious stuff (etc/hosts, /etc/sysconfig/network, /etc/sysconfig/network-scripts/ifcfg-eth0...) just follow these directions from the Scalix Wiki:

Update the Postgres Client Authentication

Changing your IP address does not update Postgres and access to the Scalix API is then denied. To rectify this you need to modify the file /var/opt/scalix/NN/postgres/data/pg_hba.conf. Remember NN is the abreviation of your Scalix node, so it will change depending on the hostname of your scalix server.
Find the line that looks like:

host    scalix      scalix      192.168.1.100/32   md5

Edit the file to change this line to look like:

host    scalix      scalix      192.168.1.50/32   md5

Update the Search and Index Service

Changing your IP address does not update the Search and Index Service properties. To rectify this you need to modify the file /var/opt/scalix/NN/sis/sis.properties. Again remember NN is the abreviation of your Scalix node!
Find the lines that look like:

index.client.whitelist=192.168.1.100,127.0.0.1

search.client.whitelist=192.168.1.100,127.0.0.1

Edit the file to change the lines to look like:

index.client.whitelist=192.168.1.50,127.0.0.1

search.client.whitelist=192.168.1.50,127.0.0.1

Update the Uber Manager Service

As above changing your IP address does not fix the Uber Manager. To fix this you need to modify the file /var/opt/scalix/NN/caa/scalix.res/config/ubermanager.properties. Again remember NN is the abreviation of your Scalix node!
Find the line that looks like:

ubermanager.notification.listener.address=192.168.1.100

Edit the file to change the line to look like:

ubermanager.notification.listener.address=192.168.1.50

Reboot and enjoy your server

After you have finished this procedure please reboot. Everything should be working just like before.
Do remember, however, that this discussion only covered Scalix. Other services or other parts of the server which depend on the IP Address instead of hostname will still need to be changed.

Installing CentOS on >2TB - this machine cannot boot using GPT

2010-06-17T12:24:00.000-07:00

Upon trying to instlal CentOS 5.5 x86 on a Dell PowerEdge the other day:

"Your boot partition is on a disk using the GPT partitioning scheme but this machine cannot boot using GPT."

idolinux.blogspot.com has a post on "Perc RAID and EFI GPT weirdness" that seemed to have a good solution, bypassing GPT entirely.

I found that configuring two virtual disks in RAID (I made VD0=2TB) works as well. Just put /boot on the VD that is (equal to or) less than 2TB.

Format External USB Drive for ext3

2010-06-09T12:50:00.000-07:00

When trying to mount a USB device that is formatted FAT32, you'll get something like mount: wrong fs type, bad option, bad superblock on /dev/sdb1. Simply format the drive for ext3:

Make sure you know what partition you're formatting, dmesg should help. Once you know, simply mkfs.ext3 /dev/sdb1

It will look something like this:

[user@localhost ~]# mkfs.ext3 /dev/sdb1

mke2fs 1.39 (29-May-2006)

Filesystem label=

OS type: Linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

60964864 inodes, 121924864 blocks

6096243 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=0

3721 block groups

32768 blocks per group, 32768 fragments per group

16384 inodes per group

Superblock backups stored on blocks:

32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,

4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,

102400000



Writing inode tables: done

Creating journal (32768 blocks): done

Writing superblocks and filesystem accounting information: done



This filesystem will be automatically checked every 36 mounts or

180 days, whichever comes first.  Use tune2fs -c or -i to override.

Ubuntu 10.04 - Move the Window Buttons Back to the Right Side

2010-05-25T08:00:00.000-07:00

From codigomanso.com, pointed out by @packetlife:

Press Alt+F2, then type gconf-editor and press enter. That’s for opening the configuration editor.

Once on this editor, in the item tree at the left, you have to look for this path app -> metacity -> general and you doubleclick on the field named button_layout.

Then, you have only to change the value field and put this:

menu:minimize,maximize,close

You save the changes, and voila!! all the windows reconfigured again!

Now all the windows show the minimize, maximize and close buttons on the right again