Archive for October 2014

Configure MXL interfaces in bulk (in ranges)

Note the spaces when using the “range” command:
FTOS(conf)#interface range Tengigabitethernet 0/1 – 32

For VLAN configuration there are no spaces …. :
FTOS(conf)#interface vlan 900
FTOS(conf-if-vl-900)#untagged Tengigabitethernet 0/52-56


How to get UUID of local storage on XenServer

[root@XenServer14 ~]# pvscan | grep Local | awk ‘{print $4}’ | sed ‘s/-/ /’ | awk ‘{print $2}’

List permissions for all directories in a path

root@wintermute:~# namei -m /root/XenBackup/Xen_PXE_Install/webroot/
f: /root/XenBackup/Xen_PXE_Install/webroot/
drwxr-xr-x /
drwx—— root
drwxrwxrwx XenBackup
drwxrwxrwx Xen_PXE_Install
drwxrwxrwx webroot

Very useful to troubleshoot Apache2 403 permission errors when the document root has been changed from the default

Use Ubuntu as a router with NAT

Setup two interfaces – one on each network
ETH0 is the outside / internet side
ETH1 is the inside / private network side (which needs internet access)

Static rule example:
root@ubuntu01:~# cat /etc/network/interfaces
# The loopback network interface
auto lo
iface lo inet loopback

# The External network interface
auto eth0
#iface eth0 inet dhcp
iface eth0 inet static

# The Internal network interface
auto eth1
#iface eth1 inet dhcp
iface eth1 inet static

Enable the inside IF
ifup eth1

Enable forwarding in current session:
echo “1” > /proc/sys/net/ipv4/ip_forward

Uncomment the section on forwarding to get permanent use of the NAT (even after rebooting):
vi /etc/sysctl.conf

Uncomment and save:

Restart networking (don’t do this over SSH – the connection will be cut):
/etc/init.d/procps restart
/etc/init.d/networking restart

Setup the actual forwarding rules in iptables:
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo iptables -A FORWARD -i eth0 -o eth1 -m state –state RELATED,ESTABLISHED -j ACCEPT
sudo iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT

Save the rules so they’re not lost at reboot:
iptables-save > /etc/iptables.rules

Windows 2012 R2 Hyper-V core – restart the Server Configuration menu from the command line


vCenter certificate location (for import into third-party certs on the DDC):


Windows 2012 R2 Hyper-V – force remove from domain (when the DC cannot be contacted):

From normal cmd (not powershell):
netdom remove %computername% /domain:%userdomain% /force

XenServer error recovery

Reset without restarting (if things are hung and aren’t going well):

View current tasks:
xe task-list

Power off VM if hung (but it can take a long time – shut down by itself while checking commands this time)
xe vm-reboot vm=(name or UUID of VM) –force

xe vm-reset-powerstate vm=(name or UUID of VM) –force

Find and Execute

find . -exec cmd -option1 -option2 — {} +


find . -print0 | xargs -0 cmd -option1 -option2 —

For example:
find . -name “*.bkp” -exec ls -l {} +

Rule the world!

Automatically logging on to Windows at startup

Start>run: netplwiz
Select Account
Uncheck box near top of dialog box