Specifications

1191
Cross-Platform Release Notes for Cisco IOS Release 12.0S
OL-1617-14 Rev. Q0
Resolved Caveats—Cisco IOS Release 12.0(28)S1
Workaround: There is no workaround.
• CSCuk51177
Symptoms: You may not be able to make a Telnet connection to a Cisco IOS platform.
Conditions: This symptom is observed when the CNS Exec Agent is used to remotely issue an
interactive CLI command.
Workaround: There is no workaround.
• CSCuk51269
Symptoms: Multicast packets such as HSRP and OSPF are not received on a port-channel interface.
Conditions: This symptom is observed when a port-channel interface is configured on a Cisco router,
when you reload the router, and when the first member is added to the port-channel interface by
entering the no shutdown interface configuration command on physical interface.
Workaround: Enter the do shutdown interface configuration command followed by the no
shutdown interface configuration command on the port-channel interface.
TCP/IP Host-Mode Services
• CSCed78149
A document that describes how the Internet Control Message Protocol (ICMP) could be used to
perform a number of Denial of Service (DoS) attacks against the Transmission Control Protocol
(TCP) has been made publicly available. This document has been published through the Internet
Engineering Task Force (IETF) Internet Draft process, and is entitled “ICMP Attacks Against TCP”
(draft-gont-tcpm-icmp-attacks-03.txt).
These attacks, which only affect sessions terminating or originating on a device itself, can be of
three types:
1. Attacks that use ICMP “hard” error messages.
2. Attacks that use ICMP “fragmentation needed and Don’t Fragment (DF) bit set” messages, also
known as Path Maximum Transmission Unit Discovery (PMTUD) attacks.
3. Attacks that use ICMP “source quench” messages.
Successful attacks may cause connection resets or reduction of throughput in existing connections,
depending on the attack type.
Multiple Cisco products are affected by the attacks described in this Internet draft.
Cisco has made free software available to address these vulnerabilities. In some cases there are
workarounds available to mitigate the effects of the vulnerability.
This advisory is posted at http://www.cisco.com/warp/public/707/cisco-sa-20050412-icmp.shtml.
The disclosure of these vulnerabilities is being coordinated by the National Infrastructure Security
Coordination Centre (NISCC), based in the United Kingdom. NISCC is working with multiple
vendors whose products are potentially affected.