Cisco Cisco IOS Software Release 12.4(23) Notas de publicación

Conditions: This symptom is observed on a Cisco platform that functions as a LAC and that runs 
Cisco IOS Release 12.3(14)T1 when a switchover occurs from one LNS to another LNS while the 
user session is brought up.

Workaround: There is no workaround. 

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Symptoms: If a PPPoE client session is timed out (e.g. due to a network outage), and a restart of the 
session is subsequently unsuccessful (e.g. because network outage persists or the PPPoE server has 
not timed out the prior session) and if the user then manually clears the session, then the router will 
no longer be able to bring up this session until a reload is performed.

Conditions: This symptom has been observed when the PPPoE session is unexpectedly interrupted 
with Cisco IOS Release 12.3(8)T8 or Release 12.3(11) T5. The next feature also needs to be 
configured.

Workaround: Use the following procedure:

Reload. 

Do not configure the DDR feature for the PPPoE session. This problem is limited to PPPoE 
client sessions using the DDR feature. 

Cisco IOS Release 12.4(3b) is a rebuild release for Cisco IOS Release 12.4(3). The caveats in this 
section are resolved in Cisco IOS Release 12.4(3b) but may be open in previous Cisco IOS releases. 

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Symptoms: A router that is running Cisco IOS may crash unexpectedly.

Conditions: NAT must be enabled for this symptom to occur. The problem is seen when an 
application uses two well known ports: one for source and the other for destination. The outgoing 
translation is created, but on the return trip, using the previous source port as the destination, NAT 
may use the incorrect algorithm.

For example, if a PPTP session is initiated to the well known port 1723 from source port 21 (FTP), 
then the outgoing packet will create a FTP translation (we look at source information when going 
from in->out). When the packet is returned, we again look at the source information to know what 
kind of packet this is. In this case we have the source port will be 1723, and NAT will assume this 
is a PPTP packet. This will try to perform PPTP NAT operations on a data structure that NAT built 
for a FTP packet and may lead to a crash.

Workaround: There is no workaround. 

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The Cisco Next Hop Resolution Protocol (NHRP) feature in Cisco IOS contains a vulnerability that 
can result in a restart of the device or possible remote code execution. 

NHRP is a primary component of the Dynamic Multipoint Virtual Private Network (DMVPN) 
feature.