managed switch doesn't allow ot change IP on my PCs

[Zahar]

What I have:

AD-domain 2003 (SBS 2003 + 10 WindowsXP). All PCs and servers are connected with managed switch hp procurve 2524. IP Subnet is 192.168.10.0/24.

Problem:

When I try to change IPs of any my PCs to new subnet (192.168.11.0/24 or 10.0.0.0/8), I'm getting "duplicate IP address" error. This error disappears only if I return PCs to 192.168.10.0/24 subnet.

This problem doesn't appear if I connect PCs with unmanaged switch hp procurve 408. With this switch I can assign any IPs/subnets I'd like.

Any ideas?

[Nameesh NR · Accepted solution]

Hi Zahar,

I think the problem that you are facing is
due to the fact that the test-pc is connected
to an untagged-port on switch 2524. And the
port belonging to Vlan that has IP/subnet
as - 192.168.10.0/24. So, the IP needs to be in the same subnet.

Here are the things I would recommend you to -
(1) Check the port to which test-pc is connected. Is the port part of VLAN that has
192.16.10.0/24 as the IP/subnet.
(2) Check if the IP has been assigned to any other test-pc on the network.
(3) Try modifying the subnet mask to /16, which can also solve the problem
with your IP assignment.

If you are still not able to solve. Some
questions for you -
(1) What is the gateway ip address
(2) VLAN tagging info of the port that is
connecting the test-pc.

Hope this helps.

Thanks,
N
(don't forget the points :))

[Zahar]

Dear Nameesh,

Thank you for the reply.

Here are more details about LAN configuration:
Switch has one default VLAN, all ports are untagged.
- 20 PCs have IPs from 192.168.10.0/24 subnet
- 1 PC has IP from 192.168.11.0/24 subnet

Now I want for PC with IP = 192.168.10.30 to assign the second IP = 192.168.11.30 to be able connect that single PC from 192.168.11.0/24 subnet.

Below you can find config of my switch:

Running configuration:

; J4813A Configuration Editor; Created on release #F.05.61

hostname "hp2524"
time timezone 120
time daylight-time-rule None
cdp run
ip default-gateway 192.168.10.99
ip timep manual 192.168.10.2
snmp-server community "public" Unrestricted
vlan 1
name "DEFAULT_VLAN"
untagged 1-26
ip address 192.168.10.111 255.255.255.0
exit
fault-finder bad-driver sensitivity high
fault-finder bad-transceiver sensitivity high
fault-finder bad-cable sensitivity high
fault-finder too-long-cable sensitivity high
fault-finder over-bandwidth sensitivity high
fault-finder broadcast-storm sensitivity high
fault-finder loss-of-link sensitivity high
no stack
no aaa port-access authenticator active

How can I solve my problem?

[Nameesh NR]

Hi Zahar,

You can configure multiple IP(s) on the pc.
But, test-pc would need to be connected to
different untag-ports on the switch.

(1) Create another VLAN on the switch
(2) Assign the IP as 192.168.11.0/24
(3) Untag some of the ports to that VLAN

Now, if you re-connect the switch from the port on 192.168.10.0/24 to
port on 192.168.11.0/24. There should be
no problem.

Here are some of my question -
(1) Do you have VLAN that has 192.168.11.0/24 subnet ?
(2) Do you have any resources on the other
subnet that you want to be accessed only
by that user ?

Hope this helps and if not you can reply back again.

Thanks
N
(don't forget the points :))

[Zahar]

Dear Nameesh,

I attached picture with small scheme of my lan. As you can see there is one server in 192.168.11.0/24 subnet that should be managed from PC with IPs configured.

Should I play with VLANs?

A person from other forum advised me to disable 'cdp' on switch. Any comments?

[Zahar]

FYI: I'd solved this problem by disabling "ARP-PROXY" feature on my gateway.

[Zahar]

See my previous post