Date: Mon, 18 Jan 2021 12:30:40 -0700 (MST)
From: Ariadne Conill <ariadne@dereferenced.org>
To: ~alpine/devel@lists.alpinelinux.org
Subject: Proposed system change: Use dhcpcd as default DHCP client
Message-ID: <eb865f14-75ae-491b-179c-f6dc9f5df49@dereferenced.org>
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Hello,

I would like to propose we use dhcpcd as the DHCP client moving forward.

## Background

At present, Alpine uses udhcpc as the default DHCP client.

With the world transitioning toward IPv6, it makes sense to use a DHCP 
client which actively supports dual-stack configurations -- dhcpcd is the 
only client we package which does so cleanly.

## Benefits to Alpine

By focusing on the dhcpcd client as our preferred DHCP client, we can 
support dual-stack IPv4+IPv6 autoconfiguration out of the box.  This is 
helpful for CPE and home router deployments, where an ISP provides DHCP 
for IPv4 and DHCPv6-PD for prefix delegation, which is the most common 
form of dual-stack deployment at the consumer ISP level.

At present, users must install dhcpcd or ISC dhclient in order to support 
this configuration -- while this is not a huge burden for the user, the 
future is trending towards network deployments which do not have IPv4 
service at all[0], which makes integrating a high quality DHCPv6 client 
into our base system a strategic priority.

By using dhcpcd by default, Alpine will support IPv4-only networks, IPv4 
and IPv6 dual-stack networks and IPv6-only networks in all possible 
auto-configuration scenarios.

Finally, dhcpcd has the best security maintenance record of the DHCP 
clients we presently support: BusyBox udhcpc, ISC dhclient and dhcpcd.

## Testing

Users can verify their setup continues to work by simply installing dhcpcd 
and testing.

## Contingency Plan

If dhcpcd has release-critical bugs, we can simply remove it from 
alpine-base, at which point BusyBox udhcpc will continue to be the default 
again.

## Timeline

I would like to add dhcpcd to alpine-base in February.

Ariadne

[0]: https://ipv4flagday.net