[Kea-users] Kea DHCP - next-server Field Does Not Accept FQDN

[Dipesh Kayastha]

Dear Kea Development Team,

I am currently working on migrating configurations from ISC DHCP (dhcpd) to
Kea DHCP and encountered a limitation regarding the next-server field.

In ISC DHCP, it is valid to specify either an IP address or a fully
qualified domain name (FQDN) for the next-server directive, as referenced
in the dhcpd.conf man page:
https://linux.die.net/man/5/dhcpd.conf

However, in Kea, the next-server field under subnet4 appears to accept only
IPv4 addresses. If an FQDN is used (e.g., "next-server": "
pxe.boot.example.com"), the configuration fails to parse and returns an
error like:


*2025-06-12 13:35:40.228 ERROR [kea-dhcp4.dhcp4/1.140187402663808]
DHCP4_CONFIG_LOAD_FAIL configuration error using **file:
/etc/config/kea4.conf**, reason: subnet configuration failed: invalid
parameter next-server : *pxe.boot.example.com*(/etc/config/kea4.conf:169:24)
*

This becomes a compatibility issue during migration, especially in
environments that rely on DNS to resolve boot server IPs dynamically.

However, ISC DHCP (dhcpd) supports both IP addresses and FQDNs in the
next-server field, as documented here:

https://linux.die.net/man/5/dhcpd.conf
[image: image.png]


Is there any plan to support FQDNs in Kea for the next-server field,
similar to how ISC DHCP handles it? FQDN support can be useful in dynamic
environments where the boot server’s IP address may change and is managed
via DNS.

I'm looking forward to hearing back from you


Regards,
.Dipesh
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.isc.org/pipermail/kea-users/attachments/20250613/b54121d1/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 93840 bytes
Desc: not available
URL: <https://lists.isc.org/pipermail/kea-users/attachments/20250613/b54121d1/attachment-0001.png>