Specifications

103
Caveats for Cisco IOS Release 12.0
78-6455-12
Resolved Caveats—Cisco IOS Release 12.0(5)
TCP/IP Host-Mode Services
• CSCdm07904
Configuring an X.25 tunneling over TCP (XOT) session over an ISDN is problematic when the
XOT sessions are closing. The ISDN session might hang up and come back up (on and off)
periodically until the underlying TCP session gets completely closed. Usually, the TCP sessions
should close, but due to a caveat in TCP for “simultaneous close,” the ISDN does not hang up until
a timeout of 8 minutes is reached. Users notice a delay of approximately 8 minutes in ISDN
hangups.
Workaround: Use the show tcp brief command to list all the TCP connections, and kill the TCP
connection (using the clear tcp tcb tcb address command) that has had the “FINWAIT1” state on
it for a long time.
• CSCdm13759
If the number of User Datagram Protocol (UDP) echo requests from different source/port pairs
causes a Cisco router to activate more than a certain number of UDP echo daemons, the remaining
UDP echos will not be replied to. There is no workaround.
• CSCdm15751
If remote copy protocol (rcp) is configured on Cisco routers, and it is used on hosts and routers
seperated by a firewall with strict access controls lists (such as allowing only loopback addresses),
the rcp sessions fail when multiple interfaces are used on the router and a second interface (other
than the primary interface) is configured for rcp sessions using the ip rcmd source-interface
command.
Workaround: Use the same IP address for second TCP connection as was use for the first, regardless
of what is set in the ip rcmd source-interface command.
Wide-Area Networking
• CSCdj80855
Under some circumstances, X.25 tuneling over TCP (XOT) service might cause a Cisco router to
reload. This condition occurs if the record of an XOT host is freed (for example, if all active
connections to that host are terminated) while an operation is executed that works with all XOT
remote host records (for example, show x25 xot). The most common way to evoke this problem is
to use the show command to report on XOT VCs from a terminal that suspends the reports with the
“-more-” prompt.
Workaround: Configure the terminal not to suspend output. For example, issue the terminal length
0 command.
• CSCdk19791
X.25 to TCP protocol translation stops sending X.25 layer-3 “acks” when using PVCs. There is no
workaround.
• CSCdk43181
A Cisco AS5800 access server running Cisco IOS Release 11.3(5)AA cannot accept ISDN calls,
but asynchronous calls are accepted.
Workaround: Dial in with a 56-kbps linespeed.
• CSCdk68801
The default input size for ISDN D channels might become set to zero. There no workaround.