HP-UX Reference (11i v2 04/09) - 4 File Formats (vol 8)
g
gated.conf(4) gated.conf(4)
default
host host
These are all the possible formats for a route filter. Not all of these formats are available in all places, for
instance the host and default formats are not valid for martians.
In most cases it is possible to specify additional parameters relevant to the context of the filter. For exam-
ple, on a martian statement it is possible to specify the allow keyword, on an import statement you
can specify a preference, and on a export you can specify a metric.
network [ exact | refines ]
network mask mask [ exact | refines ]
network masklen number [ exact | refines ]
Matching usually requires both an address and a mask, although the mask is implied in the
shorthand forms listed below. These three forms vary in how the mask is specified. In the first
form, the mask is implied to be the natural mask of the network. In the second, the mask is
explicitly specified. In the third, the mask is specified by the number of contiguous one bits.
If no additional parameters are specified, any destination that falls in the range given by the
network and mask is matched. The mask of the destination is ignored. If a natural network is
specified, the network, any subnets, and any hosts will be match. The two optional modifiers
cause the mask of the destination to be considered also:
exact
This parameter specifies that the mask of the destination must match the supplied
mask exactly. This is used to match a network, but no subnets or hosts of that net-
work.
refines
Specifies that the mask of the destination must be more specified (longer) than the
filter mask. This is used to match subnets and/or hosts of a network, but not the
network.
all This entry matches anything. It is equivalent to:
0.0.0.0 mask 0.0.0.0
default
Matches the default route. To match, the address must be the default address and the mask
must be all zeros. This is equivalent to:
0.0.0.0 mask 0.0.0.0 exact
host host
Matches the specific host. To match, the address must exactly match the specified host and the
network mask must be a host mask (all ones). This is equivalent to:
host mask 255.255.255 exact
Matching AS paths
An AS path is a list of autonomous_systems that routing information has passed through to get to this
router, and an indicator of the origin of the AS path. This information can be used to prefer one path to a
destination network over another. The primary method for doing this with GateD is to specify a list of
patterns to be applied to AS paths when importing and exporting routes.
Each autonomous system that a route passed through prepends its AS number to the beginning of the AS
path.
The origin information details the completeness of AS path information. An origin of igp indicates the
route was learned from an interior routing protocol and is most likely complete. An origin of egp indi-
cates the route was learned from an exterior routing protocol that does not support AS paths (EGP for
example) and the path is most likely not complete. When the path information is definitely not complete,
an origin of incomplete is used.
AS path regular expressions are defined in RFC 1164 section 4.2.
AS path matching syntax
An AS path is matched using the following syntax.
Section 4−−118 Hewlett-Packard Company − 42 − HP-UX 11i Version 2: September 2004