A new Apple support article states that the Lion client comes with several AFP file sharing authentication methods turned off, preventing Lion from accessing certain AFP servers. This could include most network attached storage (NAS) devices, according to PC Magazine, and, a reader reports that NetWare servers are also one of the affected servers. Group Logic last week issued an update to its AFP server, ExtremeZ-IP, which is not affected.
Lion is using Netatalk 2.2 for AFP, and is using a new authentication method called DHX2. Apple says that Lion blocks the use of older User Authentication Methods (UAM), including "Cleartxt Passwrd", "MS2.0", "2-Way Randnum exchange", and DHCAST128. To enable a blocked UAM, Apple's article describes using Terminal to edit the com.apple.AppleShareClient file in /Library/Preferences to remove a UAM from the disabled list. If you don't know the UAM used by your server, you could remove all of them from the disabled list.
Rick Zeman reported having the problem with two Novell AFP servers:
Lion clients can't mount volumes on Netware 6.5 servers using the afptcp.nlm (or Open Enterprise Server 2's AFP server) giving the error: "The version of the server you are trying to connect to is not supported. Please contact your administrator."
Apparently, Lion's AFP client only supports the DHX2 authentication mechanism which Novell evidently never rolled into either Netware or Open Enterprise Server. While Novell might fix the latter, I'm not holding out hope for the former.
If you've seen this problem or tried Apple's workaround