Cisco Cisco IOS Software Release 12.4(4)T

CSCsv52459

Symptoms: A Cisco device that is running Cisco IOS Release 12.3(7)T or later Cisco IOS code may 
see an increase in CPU usage when upgrading from a previous image.

Conditions: NAT must be enabled for the contributing factor described here to be applicable. RTSP 
and MGCP NAT ALG support was added, which requires NBAR. However, there is no way to 
disable it if that feature code is not needed.

Workaround: There is no workaround.

Cisco IOS Release 12.4(15)T7 is a rebuild release for Cisco IOS Release 12.4(15)T. The caveats in this 
section are resolved in Cisco IOS Release 12.4(15)T7 but may be open in previous Cisco IOS releases. 

The following information is provided for each caveat:

Symptoms—A description of what is observed when the caveat occurs.

Conditions—The conditions under which the caveat has been known to occur.

Workaround—Solutions, if available, to counteract the caveat.

CSCek34097

Symptoms: The router may display CPUHOG errors and/or reload when you enter the no ipv6 
multicast-routing global configuration command.

Conditions: This symptom is observed with configurations that include large numbers of dot1q 
subinterfaces.

Workaround: There is no workaround. 

CSCek52234

Symptoms: A Cisco Gigabit Ethernet Interface goes down when set to speed 100 / Full Duplex and 
when the remote end is third party LAN extension service equipment.

Conditions: This symptom has been observed on Cisco 3800 Gigabit Ethernet interface. A 
Cisco 2811 FastEthernet interface or Cisco 2821 Gigabit Ethernet do not show the problem. The 
symptom is also not seen if a Cisco Catalyst 4506 is used in place of the third party equipment.

Workaround: Use hardware other than Cisco 3800 Gigabit Ethernet when connecting to third party 
equipment. 

CSCek64863

Symptoms: DHCP Relay crashes while sending a DHCP offer to the client with binding as relay 
binding. (0.0.0.0).

Conditions:

1. Client is either not sending the client-id option or sending the MAC address as the client-id option 
in all the DHCP messages toward DHCP Relay.

2. Either smart relay is configured on the relay or relay is unnumbered so that relay bindings get 
created on the router.