Mundy

IT Knowledge Base

User Tools

Site Tools


it:dhcp_relay_in_cisco_router

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

it:dhcp_relay_in_cisco_router [2018/06/29 13:25] (current)
Dan Mundy created
Line 1: Line 1:
 +Note DHCP relay does require the dhcp service to be running.
  
 +Eg below, where 192.0.0.3 is the DHCP server:
 +
 +<​code>​
 +service dhcp
 +interface Vlan10
 +description HQ Staff Network
 +ip address 192.0.1.254 255.255.255.0
 +ip helper-address 192.0.0.3
 +!
 +interface Vlan50
 +description Wireless Vlan
 +ip address 192.0.5.254 255.255.255.0
 +ip helper-address 192.0.0.3
 +</​code>​
 +
 +{{page>​ad&​noeditbutton&​nofooter}}
 +
 +Using the DEBUG IP DHCP SERVER PACKET command, we can see what happens when a client device makes a DHCP request for an IP address:
 +
 +<​code>​
 +002121: *Apr 29 17:​37:​55.549:​ DHCPD: Reload workspace interface Vlan10 tableid 0.
 +002122: *Apr 29 17:​37:​55.549:​ DHCPD: tableid for 192.0.1.254 on Vlan10 is 0
 +002123: *Apr 29 17:​37:​55.549:​ DHCPD: client'​s VPN is .
 +002124: *Apr 29 17:​37:​55.549:​ DHCPD: using received relay info.
 +002125: *Apr 29 17:​37:​55.549:​ DHCPD: Looking up binding using address 192.0.1.254
 +002126: *Apr 29 17:​37:​55.549:​ DHCPD: setting giaddr to 192.0.1.254.
 +002127: *Apr 29 17:​37:​55.549:​ DHCPD: BOOTREQUEST from 0100.248c.6e62.52 forwarded to 192.0.0.3.
 +</​code>​
it/dhcp_relay_in_cisco_router.txt ยท Last modified: 2018/06/29 13:25 by Dan Mundy