Users connected to an ME60 access the Internet at a slow speed. Web pages
fail to be opened, and users fail to log in to applications such as QQ and MSN.
Statistics on the interfaces connecting terminals to the ME60 shows that
packets are increasing rapidly. It is found that the average size of packets
sent and received from the interfaces is merely over 80 bytes.
mirroring result and packet header obtaining on the ME60 show that may users
have sent lots of ICMP packets. These ICMP packets are scanning the network
segment of an external network, leading to traffic congestion on interfaces.
Due to reasons such as users being affected with virus, when many ICMP
packets are sent to the external network, traffic congestion occurs, affecting
the user and other users sharing the interface with this user.
1. Limit traffic
on ICMP packets so that the device discards the ICMP packets that exceed the
Acl number 10011
Rule 5 icmp
Car cir 16 cbs
2. Apply the
traffic policy to the interface. The user's ICMP scanning traffic is discarded
to ensure data forwarding..
ICMP packets are used to test connectivity. These packets
are meaningless for users' actual services. ICMP packets in this case can be
simply discarded, but that leads to a failure to use ICMP to perform tests. A
good choice is the use of CAR to control traffic.