EXP Computer PathBuilder S200 - Manual (Page 81)

Bridging 77
T0008-16F Release 5.2M
Bridge Filtering
Forcing a Local
Domain With
NetBIOS Name
Filters The NetBIOS Name Filtering feature can also force a local domain, or context, of a
NetBIOS name. All branch offices, for example, may connect to an SNA gateway
function in OS/2 by accessing a gateway local to the branch. Under normal bridging
conditions, you configure the SNA gateway NetBIOS server with a different name
for each branch office and every workstation to attach to the name for its branch
office.
With NetBIOS Name Filters, you can block the local service name (for example,
“SNA_GW”) on the WAN link so that NetBIOS broadcasts to and from that name
are not forwarded across to the internetwork.This feature lets the branches use the
same name for their local SNA service and you can configure all the workstations to
access the same local SNA name.
Wildcard Name
Patterns Name filter patterns may contain “wildcard” characters such as “?” that matches any
character or “*” at the end of the pattern that matches all remaining characters. As a
result, a single filter record can pass or block a large set of NetBIOS names. Unlike
current MAC Filter and Protocol filters for a bridge, a packet may match more than
one filter record.
For this reason, NetBIOS Name Caching operates using an ordered list of name
matching records. A packet is compared against each name matching string in order,
and the action for the first match is taken. If a packet does not match any NetBIOS
Name Filter record, the Default NetBIOS Filter Action is taken.
Another Use of
Name Filters Another way of using NetBIOS Name Filters is to pass all NetBIOS broadcasts
except those that are identified in the NetBIOS Name Filter table. This can be used,
for example, to restrict access to a particular server to the local segment.
Checking NetBIOS
Broadcasts The NetBIOS Name Filtering feature does not check every NetBIOS packet. It only
checks the NetBIOS broadcast packets that are used to initiate a session. Activating
NetBIOS Name Filtering does not affect NetBIOS sessions already in progress.