10.1 and iDisk mounting problems

Several users have reported something that we have been struggling with ourselves: the inability to mount an iDisk with Mac OS X via the Go menu or the toolbar icon. Whenever either method is attempted, the Finder becomes unresponsive, runs the rainbow cursor for over a minute, then reports that it was unable to mount the iDisk, because perhaps the account name and password are invalid. In addition, the console log reports that "webdav: 'idisk.mac.com': cannot resolve: Host Name lookup failure," followed by a timeout error.

Work-around available This does work, although it bypasses webdav, so persistent connections are not possible: select Connect to Server from the Go menu, and type "afp://idisk.mac.com," which will mount the disk after requesting your password.

Another user reports that making his primary active port the first item in the Active Ports list in the Network Preference panel fixed the problem for him. (It did not work for us, however.)

NAT the cause? There is some evidence that this problem is caused by an incompatibility with NAT (Network Address Translation). Several users who use NAT with AirPort found that bypassing NAT fixed the problem. Our ISP uses NAT, which is probably the reason we cannot get it to work. We are continuing to investigate.

(Thanks, Michael Snider, Alan Houtzer, and others.)

Update: Ben Aggus adds: "I'm currently working with our ISP on our iDisk problems. In their case, it's a layer 5 Arrowpoint switch that's causing the problem. Since Webdav uses port 80, it's subject to problems with both proxy servers, as well as caching servers. My ISP temporarily re-routed me around their caching switch and I was able to connect to iDisk successfully. I'm afraid this may be a protocol that's more advanced than some of the older equipment on the Internet can handle. This problem has apparently occurred before with Microsoft's hotmail and some other applications that use nonstandard headers on port 80. Some switches treat these as a potential DOS attack signature and disregard the packets. Webdav's site has more info."

Update: Several users report that iDisk works fine for them under NAT (see above). However, we switched one of our Macs from NAT to a fixed IP and could mount the iDisk on the first try. Clearly there is more pieces to this puzzle, and your experience may< vary.