From the whitepaper:
When a Nyzo verifier is started, it asks other verifiers for information on the current state of the blockchain. The location of verifiers are specified in the file /var/lib/nyzo/production/trusted_entry_points. In the initial distribution, the Nyzo verifiers (verifier0.nyzo.co through verifier9.nyzo.co) are listed in this file, but it may be modified at any time.
Only one verifier is allowed to be run at each IPv4 address. As nodes take very little computational power, a single system could otherwise run many instances of the Nyzo software and take a disproportionate share of transaction fees. This will prevent some users from running Nyzo verifiers in situations with shared public IP addresses (dorms, offices), but that is an acceptable limitation to ensure fairness in transaction verification. Also, this limitation does not prevent multiple Nyzo clients at an address.
Two mechanisms are in place to enforce the IPv4 address restriction. First, in the list of verifiers waiting to join the verification cycle as a new verifier, any verifier changes at an address cause that address to be demoted to the end of the queue. Second, when an existing verifier produces a block, a penalty score is applied if that verifier is not currently listed as active in the mesh. To prevent shuffling of a large set of verifiers over a smaller set of IP addresses, the verifier at an IP address is only allowed to be reassigned at a time interval slightly larger than the time interval of the current verification cycle length. So, attempts to circumvent the IPv4 address restriction will result in difficulty joining the cycle as a new verifier and will risk being removed from the cycle as an existing verifier.