CCNP: DHCP and Vlans

Node ManNode Man Member Posts: 668 ■■■□□□□□□□
Hi Everyone,
What is the relationship between dhcp and vlans. For example, if I try to set a default - router to an ip within a vlan, the switch gives an error and says that the ip in is an vlan. Must dhcp ranges be kept separate from vlan ranges?

Thanks!

Comments

  • gorebrushgorebrush Member Posts: 2,743 ■■■■■■■□□□
    There isn't really a direct relationship between them, only that a DHCP scope should only operate inside one VLAN.

    So if VLAN 10 = 192.168.10.0/24 for example, then a DHCP Server should have a physical interface attached to that VLAN servicing that DHCP scope only.

    I'm not sure what you are getting at with the question "Must dhcp ranges be kept seperate from vlan ranges?" - a DHCP scope would be inside a VLAN as I state above.

    What switch are you talking about? Are you attempting to use a switch as a DHCP server?
  • Node ManNode Man Member Posts: 668 ■■■□□□□□□□
    Hi, yes I am using a 3550 as a dhcp server. My problem is that the switch will not let the dhcp default router ip be within the vlan subnet.
  • RouteMyPacketRouteMyPacket Member Posts: 1,104
    Node Man wrote: »
    Hi, yes I am using a 3550 as a dhcp server. My problem is that the switch will not let the dhcp default router ip be within the vlan subnet.

    Why don't you post your config? There is no reason why you cannot choose an IP within the segment, you have it configured wrong but we can't guess at your config so post it

    Example:

    ip dhcp pool TEST
    network 192.168.30.0 255.255.255.0
    domain-name abc.com
    default-router 192.168.30.100
    dns-server 4.2.2.2 8.8.8.8
    Modularity and Design Simplicity:

    Think of the 2:00 a.m. test—if you were awakened in the
    middle of the night because of a network problem and had to figure out the
    traffic flows in your network while you were half asleep, could you do it?
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