Authentication: Kerberos and SideCar

Kerberos error 56: Retry count exceeded (send_to_kdc)

Problem: Attempts to use a Kerberized service result in the above error. This problem results when the network connection is blocked or not working correctly.

Solution: If you are not on Cornell campus, using EZ-Remote, or using Express Lane, check with your Internet Service Provider (ISP) to make sure that they are not using a firewall, and if they are, that they are not blocking UDP traffic on ports 749 or 750. If the firewall performs Network Address Translation (NAT), Kerberos might not work at all. This generally applies to computers on a corporate network. If you are on Cornell campus or using the modem dial-up pools, troubleshoot the faulty ethernet or modem connection. If you are using an alternate ISP, please call their tech support for troubleshooting information.

If you have any additional information regarding this problem, please contact the CIT HelpDesk via e-mail to helpdesk@cornell.edu or by phone at (607)255-8990.

Last updated March 7, 2002