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Problem with ip helper

 
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crm114
Occasional Contributor

Problem with ip helper

I have a 5412 running 15.08.0013 software.

i have 4 vlans. this is the core routing switch. i have configured ip helper on 3 vlans because the dhcp server is in the fourth vlan and doesn't need any help.

i have set the primary vlan to vlan 200, not left it at vlan 1.

when a user connects to a port in vlan 200 they get an ip address that belongs to vlan 201. If i disable the scope for vlan 201 they get an ip address for vlan 202. If i disable the 3 scopes, they get an address for vlan 200.

Could this be related to setting the primary vlan to 200?

thanks,

 

5 REPLIES
Fredrik Lönnman
Honored Contributor

Re: Problem with ip helper

Paste some relevant conf. What is a "primary vlan"?

---
CCIE Service Provider
MASE Network Infrastructure [2011]
H3CSE
CCNP R&S

crm114
Occasional Contributor

Re: Problem with ip helper

primary vlan is a config that takes some of the function off the default vlan.

paulgear
Esteemed Contributor

Re: Problem with ip helper

The primary VLAN only affects which VLAN the switch itself gets DHCP on; it doesn't have anything to do with client DHCP. (See http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c02099292&jumpid=reg_R1002_USEN for more details.)

Set "dhcp-relay option 82 replace ip" on your switch. (Unless it's already set and you removed it from the config; it would be better if you uploaded your entire switch config.)
Regards,
Paul
Fredrik Lönnman
Honored Contributor
Solution

Re: Problem with ip helper

also, what DHCP server are you running and how is it configured? I've seen some Windows DHCP servers configured with "supernet" that gave out IPs from wrong scopes when using ip-helper.

---
CCIE Service Provider
MASE Network Infrastructure [2011]
H3CSE
CCNP R&S

crm114
Occasional Contributor

Re: Problem with ip helper

You were right, the scopes were all added under a super scopes option on the dhcp server.

thanks.