Yes. These patents are garbage. pppp The claim in patent 6,282,574 is basically for ENUM, look up a name and get an IP address, but it was filed in 2000, when ENUM was already well known.
The claim in patent 6,104,711 covers a lookup that returns a primary or a backup server if the primary isn't available, filed in 1997, utterly obvious if you ever saw MX records.
Patent 6,359,880 is actually about tracking roaming cell phones, using the Internet to send the registration data. I cannot figure out how anything that Vonage does could possibly infringe, since the claims are specific to a "wireless telephone terminal".
R's,
John