How to see if an ip helper-address is configured on a VLAN

[James Cook]

Hi - I'm not exactly new to networking but this question will likely say otherwise :)

I'm trying to figure out the command to show the running-config of a VLAN.  The goal is to see if an ip helper-address has been configured on a VLAN.

This is both for a Cisco 6509 and Nexus 5k.

I simply don't know all the commands for VLANs so I can't get this info presented to me.

Thank You in advance

[m.sotnikov]

Hi,

try this command

sh ip int vlan 100 (where 100 is your VLAN id.)

you will get some like

Helper address is 172.27.1.1

[James Cook]

Thanks for the prompt reply!  Still no bueno though.

On the 6509 I get the following:

6509#show ip interface vlan xxx
                                           ^
% Invalid input detected at '^' marker.

 

On the Nexus 5K I can't complete the command, stops down at show ip interface with the following listed as ? after interface:

5K# show ip interface ?
  <CR>
  >                    Redirect it to a file
  >>                  Redirect it to a file in append mode
  A.B.C.D       Display interface for local IP address
  brief              Display summary of IP interface status and configuration
  ethernet        Ethernet IEEE 802.3z
  loopback      Loopback interface
  mgmt            Management interface
  operational   Display only interfaces that are administratively enabled
  port-channel  Port Channel interface
  vrf                   Display per-VRF information
  |                      Pipe command output to filter

[shine pothen]

try the command sh run interface vlan id one command will be seen ip helper if this command is there ip helper is enabled

[Bilal Nawaz]

Hello,

On the 6509 you can do "show run interface vlan X" and look for the helper-address command.

On the N5K's you can do the same but look for "ip dhcp relay address x.x.x.x"

Hope this helps

[shine pothen]

On 65 series the output will look like this 
Hostname#sh run interface vlan XX (command to used in enable mode)

sh run interface vlan XX
Building configuration...

Current configuration : 292 bytes
!
interface Vlan10
 ip address X.X.X.X 255.255.255.0
 ip helper-address X.X.X.X
 ip helper-address X.X.X.X
 ip helper-address X.X.X.X

-------------------------------------------------------------
on NX device the output will look like below
sh run interface vlan XXX (command to used in enable mode)

Hostname# sh run interface vlan XXX
!Command: show running-config interface Vlan132
interface VlanXXX
  no shutdown
  ip address XX.XX.XX.X/24
 ip dhcp relay address XX.XX.XX.XX

[James Cook]

Thanks - for some reason on either device this command doesn't work.  My guess is because the vlan doesn't actually have any IP or IP helper-address assigned to it.  

[Bilal Nawaz · Accepted solution]

please post the output of 'show ip int brief' on both devices. Also tell us the VLAN ID its for.

[James Cook]

yeah, the VLAN in question doesn't have any IP related config to it.  so it's not showing up in any of these commands.

will now add the IP address and helper address so it will be a layer 3 VLAN also.

Thanks everyone!

[shine pothen]

Hi 

please paste the sh run configuration. so that we can help you further

[anudeept999]

Use this command , to check helper-address status for all SVIs

Switch#sh ip helper-address
Interface Helper-Address VPN VRG Name VRG State
Vlan10 10.100.1.10 0 None Unknown
Vlan15 10.100.1.10 0 None Unknown

Hope this helps

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