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resolve host names in show ip route output

 
JitenShah
Occasional Contributor

resolve host names in show ip route output

Hi,

    i am using ProCurve J8697A Switch 5406zl (Software revision K.15.03.0005).

When I issue a "show ip route"  I get following output :

 

 

IP Route Entries

Destination Gateway VLAN Type Sub-Type Metric Dist.
------------------ --------------- ---- --------- ---------- ---------- -----

172.20.47.96/30       ev1-dev... 2000 connected 1 0
172.21.195.128/25  10-lab-et 1047     connected 1 0

 

I get ev1-dev and 10-lab-et in Gateway field. Is there any way I could get these Hosts resolved to IP addresses in the same table ?

 

Thanks.

 

5 REPLIES
Vince_Whirlwind
Trusted Contributor

Re: resolve host names in show ip route output

Those are VLAN names, not host names.

Vince_Whirlwind
Trusted Contributor

Re: resolve host names in show ip route output

Add in some static routes (ie, not "connected" subnets) and the IP address of the target interface will come up.

JitenShah
Occasional Contributor

Re: resolve host names in show ip route output

Thanks Vince_Whirlwind.

1. So these VLANS are configured on the next Hop right and not the local ones since its the Gateway.

 

2. ALso 

 

IP Route Entries

Destination Gateway VLAN Type Sub-Type Metric Dist.
------------------ --------------- ---- --------- ---------- ---------- -----

172.20.47.96/30       ev1-dev... 2000 connected 1 0
172.21.195.128/25  10-lab-et 1047     connected 1 0

 

then what are 2000 and 1047 VLANS here for ?

These VLANs (2000 and 1047) are the outgoing interface(virtual ones) right ? so a packet matching rule 172.21.195.128/25 will use one of the physical interfaces belonging to1047 VLAN as the outgoing interface right.

 

 

3. the gateway lo0  points to 127.0.0.1 .

For the below entry :

172.20.19.150/32   lo0                  connected            1          0 

Gateway is lo0 so does that mean packets destined to 172.20.19.150/32 should be dropped ?

 

4. Also most important question : how is forwarding done in these switches ? does the switch refer output of "show ip route " to make those decisions or there is another forwarding table in ProCurve J8697A Switch 5406zl (Software revision K.15.03.0005).

 

Thanks.

Vince_Whirlwind
Trusted Contributor

Re: resolve host names in show ip route output

1/ I'm not sure I understand - the routes you displayed are connected routes. They are local routes the router has legs into therefore has added to its routing table automatically.

 

2/ The VLAN ID is displayed alongside the target for the route. In this case, the target is a locally-connected VLAN, so the target is the same VLAN, by name. And yes, of you have a packet destined for 172.21.195.128/25, then it will go out VLAN 1047.

 

3/ Presumably you have configured your L0 interface with the IP address 172.20.19.150.

 

4/ show mac-address?

 

 

JitenShah
Occasional Contributor

Re: resolve host names in show ip route output

Thanks 

1 ignore this question

 

3. how can I find address configured on L0 interface. I used "show interfaces brief" and "show ip" but can not find the L0 interface. what command do we use to get all IP address configured on the box. isn't it show ip ?

 

 

4. I mean lets say we have packet with destination x.x.x.x which needs to be forwaded so does the switch refer "show ip route" table or some other  table.

like in CIsco we have show ip route but switches have Cisco Express forwarding which are like FIBs used for making forwarding decision.

SImilarly for juniper even though we have show route but they have Juniper PFE table which they use for forwarding.

 

In short if we lets say if the switch has learned 2 routes to same destination from 2 different protocols but it would use only one route from it and store in forwarding information base. I am looking for FIB table.