09-18-2003 05:40 PM - edited 03-02-2019 10:27 AM
I have a network with 10.10.0.1 255.255.192.0 with devices all over that range. How do go about fixing the network without going back to each computer and reassigning an address and netmask. Can I or how do I vlan a network with the same net mask? I have the following cisco 2620xm and cisco 2950 and a ton of cheap 48 port switches.
09-19-2003 12:39 AM
Hi,
Do any of the switches support VLANs or Trunking? If not you might have a bit of a problem. If they do not support like 802.1q vlans you will have to physically move some of the clients around or change there ip's anyway.
Regards,
Corey
09-19-2003 09:50 AM
The cisco 2950 does. Is there a way to vlan by port even if all the clients are on same subnet?
09-19-2003 11:47 AM
You normally don't setup VLANs for hosts on the same subnet.
VLAN=broadcast domain=subnet
My suggestion:
1. Hopefully you are running DHCP on your network. Set the lease time to be real short (like an hour) and wait a day or two. This will force the clients to keep requesting DHCP service more often than the default of 3 days (in Windows NT). Hopefully your network can handle this increase in traffic also.
Setup a new DHCP server (so your current one is not changed) When you are ready to implement the new IP scheme, you will disconnect your existing DHCP server from the network and connect this new one to the network. Setup mulitple DHCP scopes on this new DHCP server but don't connect it to the network yet:
scope 1 - 192.168.1.0
scope 2 - 192.168.2.0
scope 3 - 192.168.3.0
If you aren't running a DHCP server, this would be a good time to set one up and set your clients to use DHCP.
2. Configure an unused fast ethernet port on the 2620 for trunking and DHCP relay support:
interface fa0/0.1
encap dot1q 1
ip add 192.168.1.1 255.255.255.0
ip helper-address
interface fa0/0.2
encap dot1q 2
ip add 192.168.2.1 255.255.255.0
ip helper-address
interface fa0/0.3
encap dot1q 3
ip add 192.168.3.1 255.255.255.0
ip helper-address
etc...
3. setup a VTP domain on the 2950:
vlan da
vtp domain cisco
or whatever
4. Define VLANs on the 2950:
vlan da
vlan 1
vlan 2
vlan 3
or whatever.
5. Setup a port on the 2950 to trunk to the 2620 router. Note you must use a 100Mbps interface.
interface fa0/12
switchport mode trunk
6. Verify the trunk is up between the 2620 and 2950.
show int fa0/12 trunk
-----------
(Disconnect existing DHCP server from the network and connect new DHCP server to the network)
-----------
7. start putting ports on the 2950 into vlans.
After a while you should see the clients with the new IP addresses.
If you have multiple switches, setup VTP on each switch this way:
vlan da
vtp mode client
vtp domain cisco
then setup trunks between each switch.
My $.02
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide