[ale] Static DHCP Addresses? Any reason to Avoid?

[DJ-Pfulio]

On 6/11/21 9:37 PM, Neal Rhodes via Ale wrote:
...
> ARE THERE any reasons not to make this problem go away by assigning a
> fixed IP?  Then mDNS would still work where it does now, and the rest
> of us can find the little buggers without playing hunt the wumpus.

There are reasons for and against using DHCP reservations.  

Some very large organizations use DHCP reservations for everything, including servers, which I think is crazy.  I'd hate for 10-50% of my server infrastructure to fail because 2 DHCP servers aren't working or aren't accessible.

Lots of ways to address this. Much will depend on your networking needs, firewall needs, and how well the router guys can handle different subnets.

My compromised rules are:

a) all servers and desktops that do not move get locally assigned, static, IPs. Servers and desktops are on different subnets.

b) laptops and other portable computers get DHCP reserved IPs within a specific range, usually on a dedicated subnet.

c) Devices that are difficult to manually assign IPs, get DHCP addresses.  I would group them together, perhaps on a different subnet. Printers, scanners, phones, and other devices.

mDNS is a separate thing from DNS.  It is where services, zeroconf, get announced on the subnet.  I you want shares, printers, scanners, and other devices to announce themselves on the subnet, then all the clients need to be running mDNS/Avahi instances.

I've always removed avahi from my systems because it was a pain and formerly had 100% CPU sucking issues. That's changed, I think.  A desktop running avahi can connect and setup a network printer in about 20 seconds for any Linux desktop these days.

I don't have any experience with 3D printers. How hard would it be to point at a DNS name that gets put onto every device using a $20 label-maker?  Put this on the label:
      DNS-name : IP address

I've worked places where we'd have 2 inch high letters hanging down from the ceiling tiles above where devices were on the same floor with the names. Pretty handy.  Other places, the computer monitor would have a triangular sign sitting on top of the monitor with the DNS name so you'd know where to insert a tape to backup your files over the network.  Everybody loves a good tar | ssh -c tar command right?

Always remember, you have a /8 subnet to play in.
Also, while we are on subnetting, remember that avoiding commonly used subnets, like 192.168.0/24, 192.168.1/24, and the lower-end 10.1.1.0/24 will make using and running a VPN possible for more of your users.