Most reliable IP resolution in unknown LANs

I have to configure some machines that will be attached to some network of unknown properties. Maybe some Ethernet, some wireless. What configuration will provide the best propability it will work out the box?

Some ideas:

Preconfigured static V4 / V6 IPs, with the hope they don't interfere anything and no need to hop sub networks
DHCP and zeroconf/Avahi. May hop subnetworks or not depending how they are bridged. Fails if DHCP server gets unavailable for any machine.
Windows Naming Service. Maybe more often supported to hop bridged subnetworks. Akwardly unreliable in my daily experience, why?

dronus

Posted 2013-03-14T11:02:57.827

Reputation: 1 482

when you say Windows Naming Service, do you mean WINS? WINS is only for NETBios/SMB traffic, and was an option for making SMB work across subnets before NetBios over TCP was available. now a days its not necessary, but your right, it never worked reliably. either way though, it will not help with address allocation, and still relies on either a dhcp or static IP address that matches the network its jacked into. Why would you expect the DHCP server to become unavailable? – Frank Thomas – 2013-03-14T11:43:45.463

Answers

The most non-vendor-specific would be: 1) Try to query DHCP. Wait for results. 2) If none found, try to guess you an IP. Ping your guess, and use it if it seems to be empty. Can be a nasty surprise, still (another PC is rebooting or does not reply ping.) 2.5) Use 8.8.8.8 as DNS, and try to use adresses 1 and 255 as gateway to Internet. 3) Monitor logs for errors.

Barafu Albino

Posted 2013-03-14T11:02:57.827

Reputation: 245

I would definetly consider hiding all hosts behind a router to avoid conflicts and gather configuration in one place.

The "external" interface of [R] can be configured via a DHCP from the unknown network or statically. The subnet of your hosts should be configured by DHCP on [R].

The challenge of accessing your hosts from the unknown network is now limited to configuring [r], which I assume can be done.

Picking an "uncommon" subnet for your hosts such as 10.241.x.x will unlikely interfere with anything. Even if it does, changing the DHCP configuration on [R] should be trivial.

,---------------------.                   
|Unknown Network  [r]-+---[R]---#---------------------.
`---------------------'         | Your subnet of hosts|
                                `---------------------'
[r] - foreign router
[R] - your router
  # - basic switch

Ярослав Рахматуллин

Posted 2013-03-14T11:02:57.827

Reputation: 9 076