# DHCP Relaying on a Linux Host

DevFeed: [DHCP Relaying on a Linux Host](<https://devfeed.tech/articles/dhcp-relaying-on-a-linux-host-10946.md>)

Original publisher: [Read original article](<https://blog.ipspace.net/2024/02/dhcp-relaying-linux-host/>)

Published: 2024-02-28T07:02:00Z

Content type: article

Language: en

Sources: [ipSpace.net blog](<https://devfeed.tech/sources/ipspace-net-blog.md>)

Topics: [DHCP](<https://devfeed.tech/topics/dhcp.md>), [Linux](<https://devfeed.tech/topics/linux.md>), [networking](<https://devfeed.tech/topics/networking.md>), [Software](<https://devfeed.tech/topics/software.md>)

Tags: [dhcp](<https://devfeed.tech/tags/dhcp.md>), [linux](<https://devfeed.tech/tags/linux.md>), [netlab](<https://devfeed.tech/tags/netlab.md>), [networking](<https://devfeed.tech/tags/networking.md>), [software](<https://devfeed.tech/tags/software.md>)

## AI overview

The article investigates duplicate DHCP packets when ISC DHCP Relay runs on a Linux router. It finds that enabled IP forwarding causes duplicate packets, while disabling IP forwarding makes them disappear, and explains the behavior in terms of raw sockets.

## Source excerpt

Markku Leiniö sent me an interesting observation after writing a series of DHCP-relaying-related blog posts: I was first using VyOS, but it uses the ISC DHCP relay, and that software relays unicast packets. The DHCP procedures eventually worked fine, but getting sensible outputs and explanations was a nightmare. I quickly reproduced the behavior, but it took me almost half a year to turn it into a blog post. Engaging in a round of yak shaving (I wanted to implement DHCP in netlab first) didn't exactly help, either. Read more ...