Palo Alto Networks Knowledgebase: DHCP Server is not Sending Gateway and DNS IP Addresses in DHCP Offer Packet

DHCP Server is not Sending Gateway and DNS IP Addresses in DHCP Offer Packet

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Created On 02/08/19 00:04 AM - Last Updated 02/08/19 00:04 AM
Content Release Deployment
Resolution

Overview

The DHCP server is not sending gateway and DNS IP addresses in the DHCP offer packet.

 

Issue

A DHCP server configured with reserved IP addresses only is not sending gateway nor is it sending DNS IP addresses in the DHCP Offer Packet. If a DHCP server is configured on a Palo Alto Networks firewall with reserved IP addresses only, the firewall will not send gateway and DNS IP address in the DHCP offer packet.

The DHCP configuration looks like this:

dhcp {

          interface {

            ethernet1/4 {

              server {

                option {

                  dns {

                    primary 8.8.8.8;

                  }

                  lease {

                    unlimited;

                  }

                  gateway 172.16.70.70;

                }

                reserved {

                  172.16.70.100 {

                    mac 00:50:56:9E:64:96;

                  }

                }

                mode enabled;

              }

            }

          }

        }

 

The DHCP offer packet looks like this:

dhcp+1.PNG

 

Workaround

Create a dummy IP pool like the following:

dhcp {

          interface {

            ethernet1/4 {

              server {

                option {

                  dns {

                    primary 8.8.8.8;

                  }

                  lease {

                    unlimited;

                  }

                  gateway 172.16.70.70;

                }

                reserved {

                  172.16.70.100 {

                    mac 00:50:56:9E:64:96;

                  }

                }

                mode enabled;

                ip-pool 1.1.1.0/24;

              }

            }

          }

        }

 

The DHCP offer packet shows this:

dhcp+2.PNG

owner: npoprzen



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