Procurve DHCP/Vlan issue

[dalfon]

I've got a Procurve 5308XL core switch. Have set up 2 Vlans which are using Adtran routers to pass out DHCP - one to a wireless net and one to a wired student net. These are private class B networks. The problem I am having is DHCP addresses are crossing the VLAN boundaries which I can't have as confusion results. I have 8 other VLANS on the same switch which also use DHCP but have no issues. They do not use the adtran and are Class C nets. I have one Class C net using an Adtran DHCP router which I have no problem with. I am stumped as to why the Class B net addresses seem to ignore Vlan boundaries. All Adtran routers are 3305's and set up essentially the same except for the IP schemes.

I connected up a test switch which didn't even have one of the netVlans on it and it still passed the wrong address if the other router is shut down.

Routing is enabled on both the routers and the core switch by necessity and is static routes.

Any answers would be greatly appreciated.

Don D'Alfonzo
Averett University

 

[dalfon]

I realize I probably need ACLs on both vlans denying DHCP from the wrong one. I am looking for an example of how to write that on an HP.

If I'm wrong about the ACLs then I'm stumped.

Thanks,
Don
Averett

 

[unclerico]

I am stumped as to why the Class B net addresses seem to ignore Vlan boundaries.

one thing you need to realize is that VLAN != Subnet. You can run two VLANs with the exact same network configuration as long as you're not trying to route the traffic. the logical thing that should be done is to change the class b range into multiple class c's. please tell me if i'm not understanding the issue. if i'm not understanding, please post the address ranges that you're using.

I hate all Uppercase... I don't want my groups to seem angry at me all the time! =)
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[dalfon]

Thanks for the reply.. Have 3 - 3305 routers
172.16.85.0 Class C
172.16.96.0 Class C
172.18.112.0 Class B mask 255.255.248.0

All w/Dhcp scopes and connected to same HP 5308switch

If .96 is down devices connected to it will receive a 112 address.

If .85 is down device on that Vlan will not receive any address which is appropriate.

Other 8 vlans maintain Vlan integrity.


Seems more like a router issue at the moment..

Started a week ago after running fine for at least 6 months.

If I split up the Class B don't I need DHCP servers for each C created? Also don't know if I can run multiple separate nets on an Adtran routed through the same interfaces.

Don

 

[unclerico]

can you post configs from the 3305's and the 5308??

I hate all Uppercase... I don't want my groups to seem angry at me all the time! =)
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[dalfon]

Yesterday I discovered that someone (student?) had crossed the network switches with a cat5 cable in a locked closet..

Removed the cable and all is well..also changed the lock on the closet door..

The symptoms made absolutely no sense until we discovered the network loop..

Thanks very much for your interest and help..

Don
Averett

 

[unclerico]

lol, that's not good. do you have spanning-tree enabled on those guys??

I hate all Uppercase... I don't want my groups to seem angry at me all the time! =)
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