Verifying the Network Connection

Log on to the system as root.

Type /sbin/ifconfig -a to verify:

Each interface in the network is configured with the correct IP address and netmask
The network is running

For Example:

eth0      Link encap:Ethernet  HWaddr 24:6E:96:36:49:FC  
          inet addr:39.87.48.4  Bcast:39.87.48.255  Mask:255.255.255.0
          inet6 addr: fe80::266e:96ff:fe36:49fc/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1460 errors:0 dropped:0 overruns:0 frame:0
          TX packets:475 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:115412 (112.7 Kb)  TX bytes:26615 (25.9 Kb)

eth1      Link encap:Ethernet  HWaddr 24:6E:96:36:49:FD  
          inet addr:39.103.48.4  Bcast:39.111.255.255  Mask:255.240.0.0
          inet6 addr: fe80::266e:96ff:fe36:49fd/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1281 errors:0 dropped:0 overruns:0 frame:0
          TX packets:450 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:102412 (100.0 Kb)  TX bytes:23177 (22.6 Kb)

eth2      Link encap:Ethernet  HWaddr 24:6E:96:36:49:F8  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

eth3      Link encap:Ethernet  HWaddr 24:6E:96:36:49:FA  
          inet addr:10.25.17.104  Bcast:10.25.17.255  Mask:255.255.255.0
          inet6 addr: fe80::266e:96ff:fe36:49fa/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:14092 errors:0 dropped:0 overruns:0 frame:0
          TX packets:186 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1249099 (1.1 Mb)  TX bytes:21484 (20.9 Kb)

The labels eth0, eth1, and eth3 are Ethernet devices and the assigned IP addresses are displayed with the network mask and broadcast address. This indicates that the network is up and running.

If there is no output, the network has not started on the node. If there is output, but the node is not communicating over the network, check the network connections and the configuration of the network card.

Type route | sort -brk3 to display the routing table.

Output example.

Kernel IP routing table
Destination     Gateway          Genmask          Flags  Metric  Ref  UseIface
cs3096-18.labs. *                255.255.255.0    U      0       0    eth3
39.87.48.0      *                255.255.0.0      U      0       0    eth0
39.96.0.0       *                255.0.0.0        U      0       0    eth1
default         10.25.17.254     0.0.0.0          UG     0       0    eth3

In the Flags column, U indicates that the routes are up, and G indicates the gateway.

Type ping -c 3 IP_address to verify the network connection.

Output example:

# ping -c 3 10.25.17.105
PING 10.25.17.105 (10.25.17.105): 56 (84) bytes of data.
64 bytes from 10.25.17.105: icmp_seq=1 ttl=64 time=0.205 ms
64 bytes from 10.25.17.105: icmp_seq=2 ttl=64 time=0.093 ms
64 bytes from 10.25.17.105: icmp_seq=3 ttl=64 time=0.095 ms
--- 10.25.17.105 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss, time 1998ms
rtt min/avg/max/mdev = 0.093/0.131/0.205/0.052 ms

The results of the ping command in this example indicates a good connection to the network and subnets, and no packet loss. If there was any loss, refer to results from the previous steps to diagnose the problem. If a default router is available, run traceroute IP_address to localize the problem, or ping an external IP address to test connectivity.

Verifying the Network Connection - Kubernetes

Kubernetes Appliance Software Installation Guide