i am using 2 3030 concentrators doing native sdi authentication. os version 3.5.3. randomly, users will get authentication failures. i see a message in the log that the sdi server is unspecified, when in fact, it is working....other users are getting authenticated and i can ping the sdi server at the time of the failure.
I've had the same problem, and in each case (without exception) the problem has been user related. They had input either the wrong passcode, wrong pin, just the pin, just the code, yada yada. Even though it's tough to tell the users that they're putting in the wrong passcode, I'll bet that a review of the SDI logs will confirm it. The other thing to check is that your SDI server has a really accurate time reference - drift is bad in the RSA's world. If you're running on a WinTel box, check out analogx.com for a nice time sync program that's free. Best of luck.