Annoying IoT behavior

[Philip Prindeville]

Hi,

I've been trying to resolve a few issues with some IoT's of various shapes and sizes that have some really annoying behavior.

The first one was a bunch of Amazon smart dimmers on WiFi that would all use the same default hostname, which made finding them in ARP tables or on Unifi a royal pain.  The solution was to do the following:

host island-dimmer1 {
 hardware ethernet xx:xx:xx:xx:xx:xx;
 fixed-address 192.168.6.211;
 option host-name "island-dimmer1";
 if exists dhcp-parameter-request-list {
  option dhcp-parameter-request-list = concat(option dhcp-parameter-request-list, 0c);
 }
}


And force the local stack to override the hostname.  Now I can see the dimmers by the names I've given them and not "Amazon.mydomain.com <http://amazon.mydomain.com/>" or whatever.

Same for the family's Echo's and Echo Dot's.

The one that doesn't seem to work in the Apple TV's (gen 4 and gen 5) that renew their leases about every minute.

It's excessive, considering the lease time is 86400.

I tried doing:

host Living-Room-xxxxxxxxxxxx {
 hardware ethernet xx:xx:xx:xx:xx:xx;
 fixed-address 192.168.6.240;
 option host-name "Living-Room";
 if exists dhcp-parameter-request-list {
  option dhcp-parameter-request-list = concat(option dhcp-parameter-request-list, 3a);
 }
}

And indeed, if I tcpdump the DHCP traffic, I see:

...
   Vendor-rfc1048 Extensions
    Magic Cookie 0x63825363
    DHCP-Message (53), length 1: ACK
    Server-ID (54), length 4: 192.168.6.1
    Lease-Time (51), length 4: 43200
    RN (58), length 4: 21600
    Subnet-Mask (1), length 4: 255.255.255.0
    Default-Gateway (3), length 4: 192.168.6.1
    Domain-Name-Server (6), length 4: 192.168.6.1
...

But it ignores the lease time and renewal time (RN) all the same.

Anyone else come up with a good solution for misbehaving IoTs?

Thanks,

-Philip