02-19-2007 12:27 AM - edited 03-03-2019 03:48 PM
Here iam enclosing sh ip cache flow output of a router.
My question is ,what do you mean by NULL interface.why these type traffic is flowing in a router .
Fa0/1 0.0.0.0 Null 255.255.255.255 11 0044 0043 1
Fa0/0 0.0.0.0 Null 255.255.255.255 11 0044 0043 1
Fa0/0 10.17.1.198 Null 255.255.255.255 11 0208 0208 1
Fa0/1 10.17.1.198 Null 255.255.255.255 11 0208 0208 1
Fa0/0 10.17.1.197 Null 224.0.0.9 11 0208 0208 1
02-19-2007 12:39 AM
Hi
The port numbers indicate the packets are being destined to port 67 and port 520.
(520 - extended file name server,
67 - Bootstrap Protocol Server)
Port belongs 520 to extended file name server and Port 67 belongs to Bootstrap Protocol Server..
regds
02-19-2007 02:03 AM
hi Prem,
How you know these belongs to 520 and 67 ports.
sravan kumar
02-19-2007 02:21 AM
Hi
Those ports are mentioned in Hexa-Decimal numbers you can decode them using our normal basic extended calculator..
regds
02-19-2007 02:04 AM
Please go through the url you can have a better uhttp://cisco.com/en/US/products/ps5845/products_configuration_guide_chapter09186a00806f4e85.html#wp1329626nderstanding of using Null interface
02-19-2007 04:27 AM
Hi sravan,
Meaning of NULL interface is the packets dropped because of ACL. The below link gives you the information
http://cisco.com/en/US/tech/tk812/technologies_white_paper09186a008022bde8.shtmlc
Regards
S. Shantharam
02-20-2007 10:25 PM
Hi,
Suryananraya,
Iam not able to open your URL.
Regards
sravan kumar
02-20-2007 10:35 PM
hi to all,
My main intention is to block 172.0.0.0 0.255.255.255 traffic.For this i have created ACL as deny ip 172.0.0.0 0.255.255.255 any ..But when i run the command "sh ip cache flow i can see the 172 series ip address traffic.
So please help in this regard . how can i block the traffic of 172 serices.
Out put if "sh ip cache flow " here enlosed.
SrcIf SrcIPaddress DstIf DstIPaddress Pr SrcP DstP Pkts
Se5/2 172.16.19.1 Null 172.23.142.126 01 0000 0000 65
Se5/2 172.23.170.16 Null 172.23.142.207 06 1266 01BD 1
Se5/2 172.23.170.16 Null 172.23.142.81 06 1242 01BD 1
Se5/2 172.23.170.17 Null 172.23.142.250 06 0408 01BD 1
02-20-2007 11:51 PM
Hi Saravana,
Please try this link
http://cisco.com/en/US/tech/tk812/technologies_white_paper09186a008022bde8.shtml
Regards
S. Shantharam
02-20-2007 10:38 PM
Hi all,
How can i stop this traffic.
Fa0/1 0.0.0.0 Null 255.255.255.255 11 0044 0043 1
Fa0/0 0.0.0.0 Null 255.255.255.255 11 0044 0043 1
Fa0/0 10.17.1.198 Null 255.255.255.255 11 0208 0208 1
Fa0/1 10.17.1.198 Null 255.255.255.255 11 0208 0208 1
Fa0/0 10.17.1.197 Null 224.0.0.9 11 0208 0208 1
plese help me what are the command will stop the unwanted virus traffic.
regards
sravan
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