Installation guide

These networking tools can assist with troubleshooting virtualization networking problems:
ifconfig
tcpdump
The tcpdump command 'sniffs' network packets. tcpdump is useful for finding network
abnormalities and problems with network authentication. There is a graphical version of tcpdump
named wireshark.
brctl
brctl is a networking tool that inspects and configures the Ethernet bridge configuration in the
Virtualization linux kernel. You must have root access before performing these example
commands:
# brctl show
bridge-name bridge-id STP enabled interfaces
-----------------------------------------------------------------------------
xenbr0 8000.feffffff no vif13.0
xenbr1 8000.ffffefff yes pddummy0
xenbr2 8000.ffffffef no vif0.0
# brctl showmacs xenbr0
port-no mac-addr local? aging timer
1 fe:ff:ff:ff:ff: yes 0.00
2 fe:ff:ff:fe:ff: yes 0.00
# brctl showstp xenbr0
xenbr0
bridge-id 8000.fefffffffff
designated-root 8000.fefffffffff
root-port 0 path-cost 0
max-age 20.00 bridge-max-age 20.00
hello-time 2.00 bridge-hello-time 2.00
forward-delay 0.00 bridge-forward-delay 0.00
aging-time 300.01
hello-timer 1.43 tcn-timer 0.00
topology-change-timer 0.00 gc-timer 0.02
Listed below are some other useful commands for troubleshooting virtualization on Red Hat
Enterprise Linux 5. All utilities mentioned can be found in the Server repositories Red Hat Enterprise
Linux 5.
st race is a command which traces system calls and events received and used by another
process.
vncviewer: connect to a VNC server running on your server or a virtual machine. Install
vncviewer using the yum install vnc command.
vncserver: start a remote desktop on your server. Gives you the ability to run graphical user
interfaces such as virt-manager via a remote session. Install vncserver using the yum install
vnc-server command.
35.2. Log files overview
Red Hat En t erp rise Lin ux 5 Virt ualizat ion Guid e
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