Re: [Bloat] mDNS

[Matt Taggart <matt@lackof.org>]

On 2/27/24 10:52, Rich Brown via Bloat wrote:

> Exactly! There are no rules about what subnet range an ISP's gear will 
> assign to DHCP devices.
> 
> So (I believe) it becomes incumbent on OpenWrt to be smarter than the 
> ISP's router (shouldn't be hard) and pick a separate subnet for its LAN 
> & wireless interface. (Clearly, OpenWrt could default to 192.168.1.0/24, 
> but if that's that range the ISP is using, it could switch to 
> 192.168.2.0/24. I think that's all the flexibility that's required...)

Independent of which orgs are and are not allowed to use rfc1918 
addresses...

I sometimes find myself setting up openwrt routers behind other ISP 
provided NAT'ing routers that use rfc1918 addresses. Example: take a 
travel router on vacation and connect it to a network where I don't have 
any control over the ISP router, but I still want to get the advantages of:
* my ESSID with my password, all my family's wifi devices "just work"
* SQM for all the wifi/wired things I connect to it. Still could 
experience bufferbloat if there are things upstream of my router, but 
often that is zero devices, or just a "smart" tv.
* firewalling all my devices together and away from other suspect stuff

BTW the openwrt bcp38 packages have some automatic rfc1918 detection in 
order to make sure they don't setup a config that breaks in the case 
where WAN is rfc1918.

Also... starting back in the old CeroWRT days I switched to using the 
172.16 rfc1918 ranges when I realized that nobody else uses them, and 
that has been a good way to avoid collisions (but wouldn't work as an 
openwrt default).

-- 
Matt Taggart
matt@lackof.org