Question on secondary ip address

Answered Question
Aug 9th, 2008

On one of my clients site router, they have a secondary ip address configured:

interface Ethernet0/0

ip address 10.2.0.1 255.255.255.0 secondary

ip address 10.2.1.1 255.255.255.0

The switch that connects to E0/0 has an ip address of 10.2.0.2. The switch that connects to E0/0 has these interfaces:

interface Vlan1

ip address 10.2.0.2 255.255.255.0

no ip route-cache

!

interface Vlan60

ip address 10.2.60.1 255.255.255.0

Now vlan 60 isn't pingable from the router since this L3 switch doesn't have ip routing enabled. If I enable ip routing on this switch, I can't ping 10.2.0.2 anymore from the router.

Should I just delete the secondary interface 10.2.0.1 on the router or should I change the ip address of vlan 1 on the switch from 10.2.0.2 to 10.2.1.2?

What are my options.

Thanks!

I have this problem too.
0 votes
Correct Answer by Edison Ortiz about 8 years 4 months ago

From the router, you need a route to 10.2.60.0/24 by using 10.2.0.2 as the gateway.

It's not a directly connected network so you need to tell the router how to get there.

It's much easier if you enable a routing protocol between these devices.

HTH,

__

Edison.

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Edison Ortiz Sat, 08/09/2008 - 19:54

If I enable ip routing on this switch, I can't ping 10.2.0.2 anymore from the router.

Try an extended ping:

R1#ping

Protocol [ip]:

Target IP address: 10.2.0.2

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Extended commands [n]: y

Source address or interface: 10.2.0.1

Type of service [0]:

Set DF bit in IP header? [no]:

Validate reply data? [no]:

Data pattern [0xABCD]:

Loose, Strict, Record, Timestamp, Verbose[none]:

Sweep range of sizes [n]:

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.2.0.2, timeout is 2 seconds:

Packet sent with a source address of 10.2.0.1

.!!!!

HTH,

__

Edison.

Scott Fella Sat, 08/09/2008 - 20:02

That works, but i can't ping vlan 60 from the router or a switch that is trunked to that switch.

Router_Elm#ping

Protocol [ip]:

Target IP address: 10.2.0.2

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Extended commands [n]: y

Source address or interface: 10.2.0.1

Type of service [0]:

Set DF bit in IP header? [no]:

Validate reply data? [no]:

Data pattern [0xABCD]:

Loose, Strict, Record, Timestamp, Verbose[none]:

Sweep range of sizes [n]:

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.2.0.2, timeout is 2 seconds:

.!!!!

Success rate is 80 percent (4/5), round-trip min/avg/max = 1/1/4 ms

Router_Elm#ping 10.2.0.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.2.0.2, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

switch-elm-idf-a#ping 10.2.60.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.2.60.1, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

Correct Answer
Edison Ortiz Sat, 08/09/2008 - 20:07

From the router, you need a route to 10.2.60.0/24 by using 10.2.0.2 as the gateway.

It's not a directly connected network so you need to tell the router how to get there.

It's much easier if you enable a routing protocol between these devices.

HTH,

__

Edison.

Please rate helpful posts

Scott Fella Sat, 08/09/2008 - 20:25

Edison,

Thanks alot.... I enalbed the routing protocol on the router and also had to create a static route to 10.2.0.1 on the switch.

Gateway of last resort is 10.2.0.1 to network 0.0.0.0

10.0.0.0/24 is subnetted, 5 subnets

C 10.2.0.0 is directly connected, Vlan1

C 10.2.60.0 is directly connected, Vlan60

C 10.2.70.0 is directly connected, Vlan70

C 10.2.90.0 is directly connected, Vlan90

C 10.2.80.0 is directly connected, Vlan80

S* 0.0.0.0/0 [1/0] via 10.2.0.1

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