topic Re: DHCP Relay Source IP Address Behavior in Next-Generation Firewall Discussions

DHCP Relay Source IP Address Behavior

Nimbus — Thu, 15 Oct 2026 07:10:21 GMT

Attention: Global TPM team,

Could you please confirm the following DHCP Relay behavior?

When a firewall acts as a DHCP Relay agent and forwards DHCPDISCOVER messages to a DHCP server as unicast packets, is the source IP address the IP address of the interface configured as the DHCP Relay agent?

Also, if available, could you please share any public documentation or KB that explicitly describes this behavior?

Thank you.

Re: DHCP Relay Source IP Address Behavior

Nimbus — Mon, 26 Oct 2026 02:13:48 GMT

@vkrishnap @sawjain

Hello,

I would like to kindly follow up on the inquiry below, as I have not yet received a response.

Could you please let me know whether this has been reviewed?

If additional time is required for investigation, I would appreciate any status update you can provide.

Thank you for your assistance.

Best Regards,

Re: DHCP Relay Source IP Address Behavior

vkrishnap — Mon, 26 Oct 2026 08:58:12 GMT

Hi @Nimbus

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClZUCA0

The source IP address in the IP header of the unicast packet is the IP address of the interface configured as the DHCP Relay agent.