dhcpcd-discuss

Hi Tom

On 12/07/2019 19:34, t t wrote:
>     We've noticed a difference in DHCP client Discover and  Request
> messages type for a client when requesting the Interface MTU.
>
> In older version dhcpcd version 5.6.7, the DHCP Request, Option 55
> Parameter Request, List Item 26 (0x2A), Interface-MTU (for the DHCP
> server to supply the MTU size) is specified.   In dhcpcd version 6.9.3
> this List Item 26 is not included in the DHCP Request.
>
> See the two Wireshark captures for the two dhcpcd client version types.
>   dhcpcd_5.6.7_bootp.cap              (sequence #s  2,4,7, 9)
> dhcpcd_latest_6.9.3_bootp.cap  (sequence # 9, DHCP Request)
>
> Can you provide the reasoning why it was removed in version 6.9.3+ and
> if the logic can be added back into the source code?
> Or am I missing some option?

AFAIK it's never been removed.
I don't support these old versions anymore and you should upgrade as 
they contain known vulnerabilities.

Anyway, just ensure that you're setting option interface_mtu in 
dhcpcd.conf and not removing it later.

A quick test with the latest dhcpcd-7 and it works fine.

Roy