NTLM authentication will work fine, as long as neither server is configured to disallow this "lower" level of authentication (lower when compared to kerberos).

If you are in a AD domain, then as long as the Windows Services on both servers are running under the same credentials, you should be ok. Having said that, in this configuration, kerberos should be used by default.

If not in a domain, then it gets harder. The normal solution is to have exactly matched username/password accounts on both servers.

Andy