Cisco SR2016T-NA Reference Manual page 503

Chapter 3 Cisco CMTS Show Commands
Usage Guidelines The
interface. ARP packets might need to be filtered when a user on the cable network generates a large
volume of ARP traffic as part of a theft-of-service or denial-of-service attack, or when a virus is using
ARP requests to find other computers that it might infect.
The show cable arp-filter command displays the total number of ARP reply packets that have been
received and the number of ARP request packets that have been sent on the cable interface, as well as
the number of such packets that have been filtered.
To clear the counters on all interfaces, use the clear counters command. To clear the counters on a
Tip
specific interface, use the clear counters cable interface command.
Examples
The following example shows the typical output from the show cable arp-filter command on a
Cisco uBR10012 router. The displays for other Cisco CMTS platforms are similar.
Router# show cable arp-filter Cable5/0/0
ARP Filter statistics for Cable5/0/0:
Replies Rcvd: 177387 total, 1869 unfiltered, 8824 filtered
Requests Sent For IP: 68625 total, 964 unfiltered, 36062 filtered
Requests Forwarded: 7969175 total, 7213 unfiltered, 366167 filtered
Router#
Table 3-2
Table 3-2
Field
Replies Rcvd
Total
Unfiltered
Filtered
Requests Sent For IP
Total
Unfiltered
Filtered
OL-1581-08
cable arp filter command enables the filtering of ARP request and reply packets on a cable
describes the fields shown in the display.
show cable arp-filter Field Descriptions
Description
Total number of ARP reply packets received on the cable interface since
power-on.
Number of ARP reply packets that the cable interface received and accepted
while filtering was enabled using the cable arp filter reply-accept
command.
Number of ARP reply packets that the cable interface dropped while filtering
was enabled, because they would have otherwise exceeded the allowable
threshold value that was configured for the interface using the cable arp
filter reply-accept command.
Total number of ARP request packets that the cable interface was asked to
forward since power-on.
Number of ARP request packets that the cable interface sent while filtering
was enabled using the cable arp filter request-send command.
Number of ARP request packets that the cable interface dropped, because
they would have otherwise exceeded the allowable threshold value that was
configured for the interface using the cable arp filter request-send
command.
Cisco Broadband Cable Command Reference Guide
show cable arp-filter
3-7