# Forward Resolution Checks

When we want to resolve a value from a .avax domain, we need to be aware that there are many factors that can change which value a domain resolves to.

Developers integrating the Avvy Domains system may want to be aware of the following situations where a value could change, and further how we can detect those changes.

The following diagram explains which contracts are used during forward resolution:

As a security precaution, projects may want to display alerts for users when values which impact forward resolution have been changed.

The Avvy system supports logic changes using a Registry pattern. Contract addresses are discovered via a Registry.

The ContractRegistry address is 0x4832D668C2c75Fa10C597FD19B116d2E1873ED69. When a contract reference is set in the ContractRegistry it will emit a Set(string contractName, address contractAddress) event.

Contract references that may be used during resolution are:

• Domain (the main ERC721 representing the domains)
• ResolverRegistry (keeps track of which Resolver contracts should be used for resolving domains)
• NameHash (utility contract used to convert a plaintext name into an ID in the system)

Projects can monitor events emitted by the ContractRegistry to determine when and how the Avvy Domains system has been updated.

The ResolverRegistry is used to discover the contract which should be used to look up a value for a domain name. The holder of a domain can make changes to the ResolverRegistry.

The ResolverRegistry address is 0x3947d4c62C108A8A7bA3ED53AbaDcFF5D8998637. When a Resolver is set for a given domain, a ResolverSet event is fired. Projects can monitor events emitted by the ResolverRegistry to determine when resolvers have been updated.

Resolvers are recommended to emit the following events when resolution values change:

event StandardEntrySet(uint256 indexed datasetId, uint256 indexed hash, uint256[] path, uint256 key, string data);
event EntrySet(uint256 indexed datasetId, uint256 indexed hash, uint256[] path, string key, string data);

Custom resolvers can be implemented, so it is possible that some will not implement this interface.

StandardEntrySet events with key=3 would represent changes to the EVM address that resolves.