Technical data

25
Bridging Filtering
You can control the flow of packets across the router using bridging filtering. Bridging filtering lets you “deny”or
“allow” packets to cross the network based on position and hexadecimal content within the packet. This enables
you to restrict or forward messages with a specified address, protocol, or data content. Common uses are to
prevent access to remote networks, control unauthorized access to the local network, and limit unnecessary traffic.
For example, it might be necessary to restrict remote access for specific users on the local network. In this case,
bridging filters are defined using the local MAC address for each user to be restricted. Each bridging filter is
specified as a “deny” filter based on the MAC address and position of the address within the packet. Deny
filtering mode is then enabled to initiate bridge filtering. Every packet with one of the MAC addresses would not
be bridged across the router until the deny filtering mode was disabled.
Similarly, protocol filtering can be used to prevent a specific protocol from being bridged. In this case, the
protocol ID field in a packet is used to deny or allow a packet. You can also restrict, for example, the bridging of
specific broadcast packets.
Unique System Passwords
As described in the section
Security Configuration Settings
of this chapter, you can specify a unique system
override password for a remote router with the command
remote SetOurPasswd
. This “system override
password” is used instead of the general system password
only
when connecting to a specific remote router. This
allows you to set a unique CHAP or PAP authentication password for authentication of the local site by the remote
site
only
when the router connects to that remote site.
A common use would be to set a password assigned to you by Internet Service Providers (ISPs). Similarly, the
system name of the local router can be overridden when connecting to a specific remote with the command
remote
setoursysname
.