User guide

Important Notes
36
Release Notes for Cisco 2500 Series for Cisco IOS Release 12.0 T
78-5563-07 Rev.H0
Normally, a management station is not notified when an Asynchronous Transfer Mode (ATM) PVC
goes down. The ATM PVC Trap Support feature enables an agent to send the required PVC traps for
this notification. It also provides support for these PVC status tables: atmCurrentlyFailingPVclTable
and atmInterfaceExtTable.
Important Notes
The following sections contain important notes about Cisco IOS Release 12.0 that can apply to the
Cisco 2500 series.
Last Maintenance Release of Cisco IOS Release 12.0 T
Cisco IOS Release 12.0(6)T has been renamed 12.0(7)T to align this release with the 12.0(7) mainline
release. The closed caveats for Release 12.0(7)T are identical to the caveats closed in the 12.0(7)
mainline release. There was no change in the feature content of the renamed release—the features in
12.0(6)T are the same as 12.0(7)T. Release 12.0(7)T is the last maintenance release of the 12.0 T release
train.
Customers needing closure of caveats for the 12.0 T features should migrate to the 12.1mainline release,
which has the complete feature content of Release 12.0 T and will eventually reach General Deployment
(GD). Release 12.0 T is a super set of the 12.0 mainline release, so all caveats closed in the 12.0
mainline are also closed in 12.0 T.
Caveat CSCdr91706 and IOS HTTP Vulnerability
A defect in multiple releases of Cisco IOS software will cause a Cisco router or switch to halt and reload
if the IOS HTTP service is enabled, browsing to http://router-ip/anytext?/ is attempted, and the enable
password is supplied when requested. This defect can be exploited to produce a denial of service (DoS)
attack.
The vulnerability, identified as Cisco bug ID CSCdr91706, affects virtually all mainstream Cisco
routers and switches running Cisco IOS software releases 12.0 through 12.1, inclusive. This is not the
same defect as CSCdr36952.
The vulnerability has been corrected and Cisco is making fixed releases available for free to replace all
affected IOS releases. Customers are urged to upgrade to releases that are not vulnerable to this defect
as shown in detail below.
This vulnerability can only be exploited if the enable password is known or not set.
You are strongly encouraged to read the complete advisory, which is available at
http://www.cisco.com/warp/public/707/ioshttpserverquery-pub.shtml .
Cisco IOS Syslog Failure
Certain versions of Cisco IOS software may fail or hang when they receive invalid User Datagram
Protocol (UDP) packets sent to their syslog ports (port 514). At least one commonly used Internet
scanning tool generates packets that cause such problems. This fact has been published on public
Internet mailing lists, which are widely read both by security professionals and by security crackers.
This information should be considered in the public domain.