Source Address And Type Filter; Accept Xns Or Ip Filter; Xns Routing Filter - 3Com SUPERSTACK 2200 User Manual

Source Address and
Type Filter
Accept XNS or IP
Filter

XNS Routing Filter

This filter operates on the source address and type fields of a frame. It
allows XNS packets to be forwarded that are from stations with an OUI of
08-00-02. To customize this filter to another OUI value, change the literal
value loaded in the last
padded with an additional 00 to fill out the literal to 4 bytes. To customize
this filter to another type value, change the literal value loaded into the
instruction.
pushLiteral.w
name "XNS from 08-00-02"
pushField.w 12
pushLiteral.w 0x0600
ne
reject
pushLiteral.l 0xffffff00
pushField.l 6
and
pushLiteral.l 0x09000200
eq
This filter operates on the type field of a frame. It allows packets to be
forwarded that are XNS or IP frame. Note the use of the
to make a copy of the type field.
name "Forward IP or XNS"
pushField.w 12
pushTop
pushLiteral.w 0x0800
eq
pushLiteral.w 0x0600
eq
This filter operates on the type and data fields of a frame. It discards all XNS
Routing packets.
name "Drop XNS Routing"
pushField.w 12
pushLiteral.w 0x0600
ne
accept
pushLiteral.b 0x01
pushField.b 19
ne
instruction. Note that the OUI must be
pushLiteral.l
# Get type field
# Load type value
# Check for mis-match
# Toss any non-XNS frames
# Set up mask to isolate first 3
# bytes
# Get first 4 bytes of source
# address
# Top of stack now has OUI
# Load OUI value
# Check for match
# Get type field
# Push copy of type
# Load IP type value
# Check for match
# Load XNS type value
# Check for match
# Get type field
# Load XNS type value
# Check for non-XNS packet
# Forward if non-XNS packet
# Load XNS routing type
# Get XNS type
# Check for non-XNS routing
# packet
Packet Filter Examples
instruction
pushTop
A-11