Issue: Troubleshooting lost Virtual interfaces after system reboot

In The Name Of Allah The Beneficent The Merciful
 
Troubleshooting lost Virtual interfaces after system reboot Virtual network interface that has just been setup is not seen as configured after a system reboot. The virtual interface no longer shows up in the ifconfig  or netstat output.

Below steps explains the troubleshooting steps to diagnose and ensure that virtual interface is configured permanently.

Problem Symptoms:

1. can not ping virtual ip address
2. can not ping virtual hostname
3. system is not accessible via virtual IP address
4. no connection to system virutal IP/hostname
5. ifconfig return physical interfaces setup only
6. network configuration gone after system reboot

Troubleshooting each symptom :
Resolution 1. Verify the physical link level and network device media is working fine. Always check if there are any problem on network hardware level as the logical interfaces are always bound to the physical interface. As the virtual interface is dependent on the physical link and the network connect,  the virtual interfaces/hosts bound to the affect physical link will also be affected.  Please  refer to the following document to troubleshoot the physical link problems.
Resolutions 2. Verify the network driver is loaded and physical interfaces are plumbed up .

a. Check if driver module has been loaded properly.

# modinfo |grep hme

117 7bb6a000   f798   7   1  hme (10/100Mb Ethernet Driver v1.180)

b. Use the kstat and netstat commands to check driver kernel statistic and interface status.

For example:

# netstat -i

Name  Mtu  Net/Dest      Address        Ipkts  Ierrs Opkts  Oerrs Collis Queue

lo0   8232 loopback      localhost      572    0     572    0 0      0

hme0  1500 chilli        chilli         2698454 0     78747  0 0 0

c. Checked that the interfaces are plumbed using the ifconfig command:

# ifconfig -a

lo0: flags=2001000849

mtu 8232 index 1

inet 127.0.0.1 netmask ff000000

hme0: flags=1000843 mtu 150- index 2

inet 129.158.137.27 netmask ffffff00 broadcas

129.158.137.255

ether 8:0:20:b8:6:a6

hme0:2: flags=1000843 mtu 1500 index 2

inet 10.158.169.10 netmask ffffff00

Resolution 3. Verify the  the name service is properly defined in the name service switch file (nsswitch.conf(4)) and the hostname is defined in the hosts database, e.g. hosts file.Name switch file /etc/nsswitch.conf contains the information of  name service sources and lookup order. Make sure all the entries are properly specified in the intent search orders of the configured name service database.
The /etc/hosts file is used as local file database if the ‘file’ keyword appear in /etc/sswitch.conf entry definition. The hostname and the associating IP address for the virtual interface should be defined in the /etc/hosts file.
For example:

In /etc/hosts

…

10.158.169.10   logical-host hme0:2

…

Resolution 4. Verify that logical interfaces IP address or hostname entry is permanently configured.
In order to create a permanent virtual interface associated with a physical ethernet interface, the file  /etc/hostname. must exists. The  actual hostname assigned in the hosts database (e.g.: /etc/hosts) or just the IP address, must be configured  in /etc/hostname. file.
For example:
With actual IP address in /etc/hostname.hme0:2:

# cat /etc/hostname.hme0:2

10.169.158.10

Or with the hostname which has been defined in the hosts database (e.g. /etc/hosts) in /etc/hostname.hme0:2:

# cat /etc/hostname.hme0:2

logical-host

Resolution 5. Once configured, reboot the system for the changes to take effect. Execute the ifconfig and ping utilities to further verify the virtual interface status. After reboot, simply run ‘ifconfig’ to confirm if the configuration done successfully.

# ifconfig -a

lo0: flags=2001000849 mtu 8232 index 1

inet 127.0.0.1 netmask ff000000

hme0: flags=1000843 mtu 1500 index 2

inet 129.158.137.27 netmask ffffff00 broadcast 129.158.137.255

ether 8:0:20:b8:6:a6

hme0:2: flags=1000843 mtu 1500 index 2

inet 10.158.169.10 netmask ffffff00

# ping -s 10.158.169.10

PING 10.158.169.10: 56 data bytes

64 bytes from logical-host (10.158.169.10): icmp_seq=0. time=0.404 ms

64 bytes from logical-host (10.158.169.10): icmp_seq=1. time=0.220 ms

64 bytes from logical-host (10.158.169.10): icmp_seq=2. time=0.216 ms

64 bytes from logical-host (10.158.169.10): icmp_seq=3. time=0.201 ms

64 bytes from logical-host (10.158.169.10): icmp_seq=4. time=0.231 ms

^C

—-10.158.169.10 PING Statistics—-

5 packets transmitted, 5 packets received, 0% packet loss

round-trip (ms)  min/avg/max/stddev = 0.201/0.254/0.404/0.084

Resolution 6. If you have reached this stage and the virtual interface configured is not persistent, further troubleshooting is required. Please contact Sun Support with the following information:

SUN Explorer Output.