[Dnsmasq-discuss] Valid and Preferred lifetimes are not decreasing in RA's(captures)

[Buck Horn]

On 22.06.2022 at 06:52:13, Jagadeesh M via dnsmasq-discuss wrote:

>So, as per our requirement we made dnsmasq to send only one prefix 
>(clients should configure ipv6 address with only that prefix), we 
>changed dhcp-range config in dnsmasq.

You haven't disclosed whether you'd run dnsmasq on your router or on a 
separate host.

Depending on your network setup, it may not be possible to fully address 
this by configuring dnsmasq alone.

If your dnsmasq would be running on a separate host in addition to your 
router, your router would remain a source of RAs for your clients, and 
quite likely the preferred one. If your router advertises a ULA prefix, 
your clients are going to consider that for IPv6 address construction as 
advertised.

>I mean to say, always the valid and preferred lifetimes in RA(seen 
>through captures) is constant at 86400. It is not decrementing and it 
>is becoming a protocol violation.

Could you elaborate on that?

I do not see a protocol violaton here: RFC 4861 explicitly allows to 
advertise valid and preferred lifetimes as 'fixed time that stays the 
same in consecutive advertisements' as one of two ways, and it even 
defines that fixed time variant as a default.

Regards,
      Buck