My Tech Notes and Stuff: 2010

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Finding potentially unused IP addresses or invalid DNS

Disco Dancing with iTach

Likewise Open Tips

Finding unused IP addresses and invalid DNS entries

The method used in the example below will not help eliminate all invalid DNS entries or find IPs that are live yet unused, however, it will provide a fairly efficient means of finding unused IPs that are not pingable at the moment and provide a list of potentially invalid reverse lookup entries which in turn would also give you clues you need to start looking for invalid A records, etc.

For this example I am going to assume we want to find unused IP addresses and potentially invalid DNS entries for the network range 192.168.1.1-100

From the prompt of your linux host with nmap installed run:

nmap -v -sP 192.168.1.1-100|grep down |for i in `awk '{print $2}'`;do host $i;done

nmap -v -sP 192.168.1.1-100 performs ping scan and returns status for specified range
grep down - filters the list to only return non-pingable hosts
for i in `awk '{print $2}'` - filters the list further to only return the IP addresses in a loop to do the host [ip address] lookup for each IP returned

One could easily substitute host with nslookup or dig but I chose host to streamline the output for readability.

Bottom line is that if you see output similar to the following:

Host 5.1.168.192.in-addr.arpa. not found: 3(NXDOMAIN)

Then you can probably safely use 192.168.1.5 for a new device and DNS entry although it would be safer to scan the DNS table by IP for forward lookup entries first.

On the other hand, if you see output similar to:

5.1.168.192.in-addr.arpa domain name pointer name.domain.com

Then you most likely have a system that is shutdown at the moment which uses that address or an invalid/outdated DNS entry to clean up.

One could easily schedule this command to run with cron and send output to an email or ticketing system for regularly scheduled DNS maintenance

Generate Wildcard SSL for Apache 2.x using OpenSSL

openssl req -new -newkey rsa:2048 -nodes -keyout star.domain.key -out star.domain.csr

Convert an Apache Cert and Key to IIS format

openssl pkcs12 -export -out star.domain.pfx -inkey star.domain.key -in star.domain.crt

Import Key into IIS from pfx format:

Start > Run
Type in MMC and click GO
Go into the Console Tab > select Add/Remove Snap-in
Click on Add > Double Click on Certificates and click on Add > OK
Select Computer Account
Select Local Computer
Click the + to Expand the Certificates Console Tree
Right click on the Personal Certificates Store
Choose > ALL TASKS > Import
Follow the Certificate Import Wizard to import your Primary Certificate from the .pfx file. When prompted, choose to automatically place the certificates in the certificate stores based on the type of the certificate.
In your IIS manager, right-click on the site that you would like to use the certificate and select properties.
Click on the Directory Security Tab and hit the Server Certificate Button. This will start the server certificate wizard.
If you are asked what you want to do with the current certificate on the site, choose to remove it, finish the wizard, and click the server certificate button to run the wizard again.
Choose to 'Assign an existing certificate' to the site and choose the new certificate that you just imported and supply the password used to create the pfx file.
Finish the certificate wizard.
Restart the server.

Extract values within quotes from com...

Extract values within quotes from command output on Linux using perl

For example:

To obtain all values within quotes from the output of a jstack command you could

./jstack <pid> |perl -lne 'print $1 if (/"(.*)"/)'

and if you wanted a count of how many quoted values there are

./jstack 23545 |perl -lne 'print $1 if (/"(.*)"/)' |wc -l

Oracle on Linux RMAN from Netbackup t...

Oracle on Linux RMAN from Netbackup to Avamar Backup Client

I recently migrated some Oracle 10g and 11g RHEL 5 VM’s and Physical boxes from Netbackup based clients to Avamar clients with the RMAN plugin. I will create a separate post regarding automation of the AvamarClient setup and focus on the RMAN configuration for event/client driven backup here.

First thing I did before automating any of the processes was to download the required docs and binaries from the Avamar web interface. There is a Documents and Downloads link at the bottom of the page of the following sample url:

http://avamarservernameorip

Then I downloaded the Avamar Oracle Client User Guide and the appropriate binaries for the platform from the right hand column, for example:

AvamarClient-linux-rhel4-x86_64-5.0.101-32.rpm
AvamarRMAN-linux-rhel4-x86_64-5.0.101-32.rpm

Also, ask your friendly EMC Avamar installer to provide a copy of AvOracleRMAN.pdf and AvOracleDatabasePrep.pdf which provide a lot more detail than the Client User Guide.

Installation and registration of the Avamar Client

1. As root cd to location of downloaded rpms
2. Type rpm -ivh AvamarClient-linux-rhel4-x86_64-5.0.101-32.rpm
3. Type /usr/local/avamar/bin/avregister
4. Enter the fqdn of the Administrator server when prompted [avamarserver.domain.com]
5. Enter the Avamar server domain [clients] when prompted
6. The Avamar Client installation is now complete

Installation of the AvamarRMAN Plugin

1. As root cd to location of downloaded rpms
2. Type rpm -ivh AvamarRMAN-linux-rhel4-x86_64-5.0.101-32.rpm
3. Update iptables with following rules to allow secure backups and also update any firewalls to allow backup through these ports:
-A RH-Firewall-1-INPUT -m state –state NEW -m tcp -p tcp –dport 28002 -j ACCEPT
-A RH-Firewall-1-INPUT -m state –state NEW -m tcp -p tcp –dport 27000 -j ACCEPT
-A RH-Firewall-1-INPUT -m state –state NEW -m tcp -p tcp –dport 29000 -j ACCEPT
-A RH-Firewall-1-INPUT -m state –state NEW -m tcp -p tcp –dport 8672 -j ACCEPT
4. Create a new user account that will have access to backup/restore jobs on the domain containing the Oracle backup jobs using the Avamar Administrator Console.
5. Create a my-avtar-flags.txt file for linux in /usr/local/avamar/bin containing:
–pidname=Oracle
–pidnum=1002
–logfile=/usr/local/avamar/var/avtar.log
–vardir=/usr/local/avamar/var
–id=[userid from prior step]
–ap=[password from prior step]
–path=[/domain/oracleservername]
–expires=[number in days]
6. Create RMAN scripts (avorabackup and avorarestore) that can be launched with cron or scheduler of your choosing, examples below:

launch this example backup script from a file named avorabackup as follows:

rman target / nocatalog @avorabackup

run {
configure device type sbt clear;
allocate channel c1 type ‘SBT_TAPE’ PARMS=”SBT_LIBRARY=/usr/local/avamar/lib/libobk_avamar64.so, ENV=(PATH=/bin:/usr/bin:/usr/local/avamar/bin)” format ‘%d_%U’;
send ‘”–flagfile=/usr/local/avamar/bin/my-avtar-flags.txt” ‘;
send ‘”–sysdir=/usr/local/avamar/etc” “–bindir=/usr/local/avamar/bin” “–vardir=/usr/local/avamar/var”‘;
configure retention policy to recovery window of 10 days;
configure retention policy to redundancy 2;
backup database plus archivelog;
delete noprompt obsolete;
crosscheck backupset;
release channel c1;
}

launch this example restore script from a file named avorarestore as follows:

rman target / nocatalog @avorarestore

run {
allocate channel c1 type ‘SBT_TAPE’ PARMS=”SBT_LIBRARY=/usr/local/avamar/lib/libobk_avamar64.so, ENV=(PATH=/bin:/usr/bin:/usr/local/avamar/bin)” format ‘%d_%U’;
send channel=’c1′ ‘”–flagfile=/usr/local/avamar/bin/my-avtar-flags.txt” ‘;
send ‘”–sysdir=/usr/local/avamar/etc” “–bindir=/usr/local/avamar/bin” “–vardir=/usr/local/avamar/var”‘;
restore database;
recover database;
release channel c1;
}

NTP Update PoSH for ESX

$Cluster = "<cluster name>"

$Hosts = Get-Cluster $Cluster | Get-VMHost

ForEach ($Host in $Hosts)

{

Remove-VmHostNtpServer -NtpServer "x.x.x.x" -VMHost $Host | Out-Null

Add-VmHostNtpServer -NtpServer "ntp0.sysxperts.com" -VMHost $Host | Out-Null

Add-VmHostNtpServer -NtpServer "ntp1.sysxperts.com" -VMHost $Host | Out-Null

Get-VMHostService -VMHost $Host | Where-Object {$_.key -eq "ntpd"} | Restart-VMHostService Confirm:$false | Out-Null

write "NTP Server was changed on $host"

}

Enabling a VirtualBox Win7 guest to connect to 8021x

Enabling a VirtualBox Win7 Guest to Connect to 802.1x Corporate Network

Disable everything but the VirtualBox Bridged Networking Driver on the interface connected to the corp. LAN and also disable authentication as this will be handled by the guest OS.

Disable VirtualBox on the interface connected to your Internet enabled network

Create 1 bridged interface and 1 host only interface on your VirtualBox Guest under Virtual Box Settings then power on Guest and go to Network Connections to verify

On the bridged interface you will enable authentication for 802.1x and edit settings as follows.

Settings - edit servernames with your own Domain Controllers/802.1x auth providers

Additional settings - Set to User Authentication and replace credentials with your Domain auth in the form DOMAINNAME\username

On the Host Only interface set it to a static IP in the same range as that which is configured on the Host as shown under File > Preferences > Network

Now you should be able to join your Windows 7 guest to the domain and access corporate resources with 802.1x authentication.

And your shared local drive too if you added under Devices > Shared Folders