The Palo Alto Networks firewall has predefined system limits for telnet access. Telnet for management is limited to 10 sessions from the same IP address.
If more than 10 telnet sessions from the same IP is attempted, the following error will appear in /var/log/messages (which is included in the Tech Support File):
Jul 10 18:54:30 5000 xinetd[1759]: FAIL: telnet per_source_limit
rom=::ffff:172.16.21.254
Jul 10 18:54:30 5000 xinetd[2368]: socket bind: Invalid argument (errno = 22)
Jul 10 18:54:30 5000 xinetd[2368]: Failed to contact identity server at
:ffff:172.16.21.254: system error
Note: An SSH connection is not counted as a telnet session.