02-01-2019 04:35 PM
Hello,
I'm pretty new to my studies, but have built a small home lab for practice. Today I configured two 2960 and one 3560 with with separate vlans and trunks. Everything seems to be working other than DHCP.
Running config from router:
R1#sh run
Building configuration...
Current configuration : 2090 bytes
!
! Last configuration change at 22:55:42 UTC Fri Feb 1 2019
!
version 15.1
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
!
enable secret 5 $1$X0BP$FgWpZ9gXsyeXW4TZXMN5O0
!
no aaa new-model
!
dot11 syslog
ip source-route
!
!
!
ip dhcp excluded-address 192.168.1.1 255.255.255.0
ip dhcp excluded-address 192.168.1.255 255.255.255.0
ip dhcp excluded-address 192.168.2.1 255.255.255.0
ip dhcp excluded-address 192.168.2.255 255.255.255.0
ip dhcp excluded-address 192.168.3.1 255.255.255.0
ip dhcp excluded-address 192.168.3.255 255.255.255.0
!
ip dhcp pool VLAN101
network 192.168.1.0 255.255.255.0
default-router 192.168.1.1
dns-server 4.2.2.2 8.8.8.8
!
ip dhcp pool VLAN102
network 192.168.2.0 255.255.255.0
default-router 192.168.2.1
!
ip dhcp pool VLAN103
network 192.168.3.0 255.255.255.0
default-router 192.168.3.1
!
!
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
crypto pki token default removal timeout 0
!
!
!
!
license udi pid CISCO1841 sn FTX0951Z126
!
redundancy
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
no ip address
duplex auto
speed auto
!
interface FastEthernet0/0.101
encapsulation dot1Q 101
ip address 192.168.1.1 255.255.255.0
!
interface FastEthernet0/0.102
encapsulation dot1Q 102
ip address 192.168.2.1 255.255.255.0
!
interface FastEthernet0/0.103
encapsulation dot1Q 103
ip address 192.168.3.1 255.255.255.0
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
interface Serial0/0/0
no ip address
shutdown
no fair-queue
clock rate 125000
!
interface Serial0/0/1
no ip address
shutdown
clock rate 125000
!
interface Serial0/1/0
no ip address
shutdown
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
logging esm config
!
!
!
!
!
!
control-plane
!
!
!
line con 0
password 7 01100F175804
logging synchronous
line aux 0
line vty 0 4
password 7 13061E010803
login
transport input all
!
scheduler allocate 20000 1000
end
My end goal was to configure ROAS with three vlans (one for each switch)
Any help is greatly appreciated!
02-01-2019 04:47 PM
Do you have configured helper ?
ip helper-address x.x.x.x
02-01-2019 04:48 PM
02-01-2019 04:54 PM
here is the sample config guide to understand also how that works.
https://www.freeccnaworkbook.com/workbooks/ccna/configuring-an-ip-dhcp-helper-address
02-01-2019 05:08 PM - edited 02-01-2019 05:09 PM
You don't need IP helper addresses because the pools are on the router.
Can you change these entries -
ip dhcp excluded-address 192.168.1.1 255.255.255.0
ip dhcp excluded-address 192.168.1.255 255.255.255.0
ip dhcp excluded-address 192.168.2.1 255.255.255.0
ip dhcp excluded-address 192.168.2.255 255.255.255.0
ip dhcp excluded-address 192.168.3.1 255.255.255.0
ip dhcp excluded-address 192.168.3.255 255.255.255.0
to
ip dhcp excluded-address 192.168.1.1
ip dhcp excluded-address 192.168.2.1
ip dhcp excluded-address 192.168.3.1
you have defined the exclusions incorrectly ie. you should have the start IP and optionally the end IP but you have used a subnet mask as the second argument and I think the router is excluding all IPs in the pools.
You do not need to exclude the broadcast address for the subnet, the router will not hand that out as a DHCP IP.
Jon
02-01-2019 05:20 PM
@Jon Marshall you are right, i missed that..looks like i am missing the numbers today.. Good catch and thank you.
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