Re: Why does dhcpd have a routers (plural) option for a subnet?

On 2024-09-25 21:04, Steve Rikli wrote:
> On Wed, Sep 25, 2024 at 08:39:39PM +0100, Frank Leonhardt wrote:
>> Ever wondered why there's a "routers" option in dhcpd.conf? I have. 
>> Why
>> isn't in just "router", as surely you can only have one default 
>> gateway?
>> Except that's been muddied a bit by MSFT.
>> 
>> Rather than adding a second just to see what happens I thought I'd 
>> ask?
>> 
>> I expect it's a mistake in the early days of dhcpd that was too late 
>> to fix,
>> or left for further expansion.
> 
> Fwiw, dhcp-options(5) says:
> 
>     option routers ip-address [, ip-address ...];
>          The routers option specifies a list of IP addresses for 
> routers
>          on the client's subnet.  Routers should be listed in order of
>          preference.
> 
> That said, I've never really tried multiple address there either.  :-)

That's interesting! I was looking in man dhcpd.conf and elsewhere, but 
not this man page (which appeared in FreeBSD 4.0 - I've just checked).

This would require the host to rotate on failed gateways. I've always 
thought this was a sensible and simple idea but networking geeks said it 
was a really bad one and router standby protocols were the way to go.

So the next interesting question would be which host stacks would accept 
multiple gateways and what would they do with them?