12-12-2009 11:37 PM - edited 03-06-2019 08:55 AM
Hi,
I have one 4500 Core switch and currently have one DHCP Server .
But now the client requires one more DHCP Server in their network for redundancy or Failover in the same VLAN.
Is it possible to have multiple DHCP servers in a single VLAN ??
Pls advice..
Thanks ,
Mahesh
12-13-2009 12:19 AM
yes it is possible.
the first that will answer will offer the IP address.
but in order to avoid ip conflict devide your IP scope in 2 parts :
for example if you have the range 192.168.1.1 ---> 192.168.1.254 then give server 1 the scope: 192.168.1.1 ---> 192.168.1.128 and server 2 :
192.168.1.129 ---> 192.168.1.254
or try to see if you can form a DHCP server cluster.
think also about implementing DHCP snooping to avoid DHCP attacks
12-13-2009 01:03 AM
hi ,
thanks for the reply...
If we have multiple vlans in the network.. is there any changes to be done to VLAN interface config in my L3 switch ?
currently i have one ip helper address < dhcp server 1> configured on the vlan interface .
Please revert.
Thanks ,
12-13-2009 02:10 AM
magesh2005 wrote:
hi ,
thanks for the reply...
If we have multiple vlans in the network.. is there any changes to be done to VLAN interface config in my L3 switch ?
currently i have one ip helper address < dhcp server 1> configured on the vlan interface .
Please revert.
Thanks ,
Yes, you will need to add a second "ip helper-address x.x.x.x" command under your L3 vlan interfaces for the 2nd DHCP server.
Jon
12-13-2009 02:49 AM
yes you can have multiple dhcp servers for a vlan.
and the ip helper command is used to just convert the broadcast packet and send it as a unicat packet to the ip add defined in the command this command is mostly used when you have the dhcp server in a diff vlan.
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