DHCP problem cat6506

iraira · ‎07-13-2004

There is also a redundant supervisor

I configured different vlan's for users and a unique vlan for

server applications.

Users are assumed to get ip addr from 2 DHCP servers on Servers Vlan.

Each vlan has HSRP group.

I'm testing first results and I'm not able to fix problem: none

of client stations gets an ip address from DHCP Servers.

Connectivity between different vlans has been tested with pings,

even from servers.

Now if a change client vlan and i force it to be on servers vlan, obviuosly

I get an ip addr in the range of the servers subnet.

Ihave configured ip helper-address on eahc user's vlan interface pointing to

both DHCP servers, ip forward protocol udp is also enabled. Each user port is set

to spantree portfast.

I sniffed and check that request from clients are sent:

source 0.0.0. dest 255.255.255.255 but no response.

Using a sniffer I have checked servers port BUT NO reeuest is sent.

Did also debug ip udp on MSCF and checked that received udp client request

src 0.0.0.0 port 68 to dest 255.255.255.255 port 68 is inmedialtely sent

with source vlan_interface_ip_addres port 67 to dhcp_ip_addr port 67, but

no reply received.

Check on forum similar problems reported but none of them solved it.

Read something about ip dhcp relay forward spanningtree, giaddr, and IOS

12.1 but not sure about if it could help me.

Need urgent help.

Thx 2 everybody

steve.busby · ‎07-13-2004

Can you post your config(s)?

iraira · ‎07-13-2004

I cannot do it now

I 'll try to post it tomorrow

Thx for your quick reply

iraira · ‎07-13-2004

I cannot do it now

I 'll try to post it tomorrow

Thx for your quick reply

iraira · ‎07-14-2004

Here there are.

I have only let confogs regarding vlan 4 (DHCP vlan)

and vlan 16 (users vlan).

Except mistakes everything looks like configs.

iraira · ‎07-14-2004

Great news,

It is working.

Problem is assumed to be in DHCP server configuration.

We have 2 DHCP servers and the first one was inactive yesterday. After a few test today this one is working fine but we are unable to fix the second one (the one we were testing yesterday).

In summary configuration is OK.

Problems are elswhere.

ymj · ‎07-15-2004

1. You said you have 2 DHCP servers but you only have one target as Helper address !

2. Are the DHCP scopes split so that they dont overlap from one server to another ?

3. Or are you using the Failover protocol ?

Well, Tell us more about your DHCP server setup, and what type of software/release you're using (ISC DHCP, MS DHCP, Cisco Network Registrar... ??)

iraira · ‎07-15-2004

Ok,

2 DHCP,

We have modified helper-address: senetences one to each DHCP.

DHCP servers have exactly the same scope.

DHCP are MS DHCP installed on VMWARE Virtual Machine.

No fialover mechanism.

We tested again this morning and OK.

ymj · ‎07-15-2004

What ?

You have the same scopes/ranges on both DHCP servers ?

Well it's going to be a real mess in your network

--> clients will get duplicate IP addresses

--> or if you DHCP server has the "ping before allocate" feature, you'll get many "Unavailable" IP addresses in your scopes, and you'll end up with exhausted pools.

regards,

iraira · ‎07-13-2004

Sorry the typos,

some parts of the text arre miising.

Here they are

"Hi,

i have a 6506 withc CatOs 8.1.3 and MSFC IOS 12.1.11B E4..."

steve.busby · ‎07-14-2004

Thanks for the partial configs.

Earlier you stated you had two DHCP servers, but I only see one referenced under VLAN16 ip helper-address.