01-14-2011 08:41 AM
I am trying to configure a DHCP sever on a FCX running layer 2 software and the "ip dhcp-server" command is not available. I have checked the configuration guide and this feature is supported...
01-25-2011 05:26 PM
I cannot see any way to apply a scope to a specific VALN.
Are you saying that VLAN X does not receive a DHCP lease or what all VLANs are recevice leases and you want to appliy to only one VLAN?
One way locking down to one VLAN might be a ACL. Need more infoprmation sorry.
01-26-2011 12:14 PM
Interestingly, there's no "base layer 3" code for the FCX.
The Layer 3 ("R"outing) code supports all features except BGP4, which requires an "ADV" software license but runs from the same image, most recently FCXR07200a.bin. So all FCX code, L2 & L3, now supports DHCP server.
01-26-2011 01:36 PM
At least on an FCX running 7.2.00a Layer 3, the DHCP server seems pretty smart about VLANs and subnets. My laptop gets an address when connected to a port that's in a vlan which has a router-interface with an IP in the DHCP pool subnet. It does NOT get an address when in a VLAN with a router-interface in a different subnet.
pool is 126.96.36.199/24
untagged e 1/1/2
router-interface ve 2
interface ve 2
ip address 188.8.131.52/24
Port 2 has DHCP.
Port 3 doesn't.
So with Layer 3 code, one way to limit DHCP to a specific VLAN is to make sure that other VLANs are assigned IPs in subnets different from the DHCP pool. Or if you create another pool for the second subnet, DHCP will work correctly on both subnets. You'd think they planned it ;-)
NOTE: When testing, if you move a device between VLANs/pools, end the lease using clear ip dhcp-server binding A.B.C.D so it will issue a different IP to the MAC that moved.
01-28-2011 11:42 PM
This may work for you - though I normally use this layer 3 VLANs. Give it a try.
Configuring an IP helper address
To forward a client broadcast request for a UDP application when the client and server are on
different networks, you must configure a helper address on the interface connected to the client.
Specify the server IP address or the subnet directed broadcast address of the IP subnet the server is in as the helper address.
You can configure up to 16 helper addresses on each interface. You can configure a helper
address on an Ethernet port or a virtual interface.
To configure a helper address on interface 2 on chassis module 1, enter the following commands.
FastIronconfig)# interface ethernet 1/2
FastIron(config-if-1/2)# ip helper-address 1 184.108.40.206
The commands in this example change the CLI to the configuration level for port 1/2, then add a helper address for server 220.127.116.11 to the port. If the port receives a client request for any of the applications that the Layer 3 Switch is enabled to forward, the Layer 3 Switch forwards the client request to the server.
Syntax: ip helper-address
The <num> parameter specifies the helper address number and can be from 1 through 16.
The <ip-addr> command specifies the server IP address or the subnet directed broadcast address
of the IP subnet the server is in.
You would configure this in the VLAN