02-08-2011 03:56 PM - edited 03-04-2019 11:21 AM
Hi,
I would like to ask for some solutions about the problem that I am havving right now.
My aim was to remove the DCHP Pool on the router and add the IP helper address to get their IP address from a remote DHCP server.
After removing and adding some configurations. Some of the PC's could not get their IP address. But come of the PC's managed to have an address.
== Original Configuration ==
R01#
!
version 12.3
service tcp-keepalives-in
service tcp-keepalives-out
service timestamps debug datetime localtime
service timestamps log datetime localtime show-timezone
service password-encryption
!
hostname R01
!
!
!
!
!
!
ip dhcp excluded-address 192.168.2.120 192.168.2.126
!
!
!
!
!
interface FastEthernet0/0
description Connection to LAN
ip address 192.168.9.254 255.255.255.0 secondary
ip address 192.168.2.126 255.255.255.192
ip accounting output-packets
speed 100
full-duplex
no cdp enable
!
!
ip classless
!
ip dhcp excluded-address 192.168.2.120 192.168.2.126 ======remove
ip dhcp excluded-address 192.168.9.151 192.168.9.254
ip dhcp excluded-address 192.168.9.152 192.168.9.254
ip dhcp excluded-address 192.168.9.153 192.168.9.254
ip dhcp excluded-address 192.168.9.154 192.168.9.254
ip dhcp excluded-address 192.168.9.155 192.168.9.254
ip dhcp excluded-address 192.168.9.156 192.168.9.254
ip dhcp excluded-address 192.168.9.157 192.168.9.254
ip dhcp excluded-address 192.168.9.158 192.168.9.254
ip dhcp excluded-address 192.168.9.159 192.168.9.254
ip dhcp excluded-address 192.168.9.192 192.168.9.254
ip dhcp excluded-address 192.168.9.193 192.168.9.254
ip dhcp excluded-address 192.168.9.194 192.168.9.254
ip dhcp excluded-address 192.168.9.195 192.168.9.254
!
ip dhcp pool USERS1 ======remove
network 192.168.2.64 255.255.255.192
dns-server 192.168.32.162 192.168.16.163 192.168.1.201
default-router 192.168.2.126
!
ip dhcp pool USERS2 ======remove
network 192.168.9.0 255.255.255.0
dns-server 192.168.32.162 192.168.16.163 192.168.1.201
default-router 192.168.9.254
!
== New Configuration ==
R01#
!
version 12.3
service tcp-keepalives-in
service tcp-keepalives-out
service timestamps debug datetime localtime
service timestamps log datetime localtime show-timezone
service password-encryption
!
hostname R01
!
!
!
!
!
!
ip dhcp excluded-address 192.168.2.120 192.168.2.126
!
!
!
!
!
interface FastEthernet0/0
description Connection to LAN
ip address 192.168.9.254 255.255.255.0 secondary
ip address 192.168.2.126 255.255.255.192
ip helper-address 192.168.1.201 ==============added
ip helper-address 192.168.1.202 ==============added
ip accounting output-packets
speed 100
full-duplex
no cdp enable
!
!
ip classless
02-08-2011 10:52 PM
hello!
i think the problem is the secondary ip address. Whenever a router sources an IP packet, it will always come from the primary IP address on the interface.
So if the PC gateway is the secondary IP you have a Problem
Martin
02-08-2011 11:41 PM
if you want to forward DHCP packets with giaddr set to secondary ip of an interface use
"ip dhcp smart-relay" in global config mode along with "ip dhcp helper-address"
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