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DHCP Issue on 3560 Switch

DeeBeeArgh
Level 1
Level 1

Hi all,

I'm aiming to achieve something so simple I cannot believe it isn't working already!

Essentially I have a 24 port 3560 switch in our company DMZ. All ports on the switch are in VLAN98 (DMZ VLAN). A few servers with static IPs in the relevant range (192.168.98.0/24) are currently connected to the switch and work just fine.

I now want to create a DHCP pool on this switch as it is going to provide IP addresses for hosts connecting to public WiFi in the building.

The pool is as follows:

Start Address: 192.168.98.192

End Address: 192.168.98.254

x2 excluded addresses: 192.168.98.198 & 192.168.98.199

Default gateway: 192.168.98.1

Granted the address block is a little odd but I needed to grab the end of the subnet range in a way that would be easy to summarise the IP addresses for the firewall ACL (wanted to use 192.168.98.200-254 but 192.168.98.192 was the closest summary for that)

My switch config looks as attached - I have used Cisco documentation to do it but my connected client is not getting an IP address and the "debug dhcp" command has resulted in no output so far.

It's gotta be something silly but I cant see what. Any help greatly appreciated.

(The client is plugged into fa0/2 - all other unused ports are in the shutdown state)

1 Accepted Solution

Accepted Solutions

Roman Rodichev
Level 7
Level 7

that won't work. You pool must be a /24 if it's a /24

ip dhcp excluded-address 192.168.98.1 192.168.98.192

ip dhcp excluded-address 192.168.98.198 192.168.98.199

!

ip dhcp pool DMZ_Pool

   network 192.168.98.0 255.255.255.0

   default-router 192.168.98.1

   lease 30

View solution in original post

3 Replies 3

Roman Rodichev
Level 7
Level 7

that won't work. You pool must be a /24 if it's a /24

ip dhcp excluded-address 192.168.98.1 192.168.98.192

ip dhcp excluded-address 192.168.98.198 192.168.98.199

!

ip dhcp pool DMZ_Pool

   network 192.168.98.0 255.255.255.0

   default-router 192.168.98.1

   lease 30

DeeBeeArgh
Level 1
Level 1

Just realised the pool is a bit backwards so config has changed a bit.

Have opted to have the whole 192.168.98.0/24 subnet in the pool and have excluded 192.168.98.1-192.168.98.199 as below:

no ip dhcp use vrf connected

ip dhcp excluded-address 192.168.98.1 192.168.98.199

!

ip dhcp pool DMZ_Pool

   network 192.168.98.0 255.255.255.0

   default-router 192.168.98.1

   lease 30

Cheers Roman - we must have been typing in sync!

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