.\" $OpenBSD: bgpd.conf.5,v 1.3 2003/12/24 13:49:21 henning Exp $
.\"
.\" Copyright (c) 2003 Henning Brauer <henning@openbsd.org>
.\" Copyright (c) 2002 Daniel Hartmeier <dhartmei@openbsd.org>
.\"
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.Dd December 23, 2003
.Dt BGPD.CONF 5
.Os
.Sh NAME
.Nm bgpd.conf
.Nd Border Gateway Protocol daemon configuration file
.Sh DESCRIPTION
The
.Ar bgpd
daemon implements the Border Gateway Protocol version 4 as described
in RFC 1771.
.Sh SECTIONS
The
.Nm
config file is divided into three main sections.
.Bl -tag -width xxxx
.It Cm Macros
User-defined variables may be defined and used later, simplifying the
configuration file.
.It Cm Global configuration
Global settings for the bgpd daemon.
.It Cm Neighbors and Groups
.Ar bgpd
establishes sessions with
.Ar neighbors .
The neighbor definition and properties are set in this section, as well as
grouping neighbors for the ease of configuration.
.El
.Pp
With the exception of
.Cm macros
the sections should be grouped and appear in
.Nm
in the order shown above.
.Sh MACROS
Much like
.Xr cpp 1
or
.Xr m4 1 ,
macros can be defined that will later be expanded in context.
Macro names must start with a letter, and may contain letters, digits
and underscores.
Macro names may not be reserved words (for example
.Ar AS ,
.Ar neighbor ,
.Ar group ) .
Macros are not expanded inside quotes.
.Pp
For example,
.Bd -literal -offset indent
c7206="1.2.3.4"
neighbor $c7206 {
	remote-as 65001
}
.Ed
.Sh GLOBAL CONFIGURATION
There are quite a few settings that affect the operation of the
.Ar bgpd
daemon globally.
.Bl -tag -width xxxxxxxx
.It Ar AS
Set the local Autonomous System number.
The AS numbers are assigned by local RIRs, such as
.Bl -tag -width xxxxx -compact
.It Ar RIPE
for Europe,
.It Ar ARIN
for America and
.It Ar APNIC
for the Asian-Pacific region.
.El
.Pp
For example,
.Bd -literal -offset indent
AS 65001
.Ed
.Pp
sets the local
.Ar AS
to 65001.
.It Ar bgpid
Set the bgp id to the given IP address which must be local to the
machine.
.Bd -literal -offset indent
bgpid 10.0.0.1
.Ed
.Pp
If not given the bgp id is determined as the biggest IP address assigned
to the local machine.
.It Ar holdtime
Sets the holdtime in seconds.
The holdtime is reset to its initial value every time either a
.Em KEEPALIVE
or an
.Em UPDATE
message is received from the neighbor.
If the holdtime expires the session is dropped.
The default is 90 seconds.
Neighboring systems negotiate the holdtime used when the connection is
established in the
.Em OPEN
messages.
Each neighbor announces its configured holdtime, the smaller one is
then agreed on.
.It Ar holdtime min
The minimal accepted holdtime in seconds.
Must be greater or equal to 3.
.It Ar listen on
Specify the local IP address the
.Ar bgpd
daemon should listen on.
.Bd -literal -offset indent
listen on 127.0.0.1
.Ed
.It Ar no fib-update
Do not update the Forward Information Base aka the kernel routing table.
.El
.Sh NEIGHBORS AND GROUPS
.Ar bgpd
establishes TCP connections to other BGP speakers, called neighbors.
Each neighbor is specified by a neighbor section, specifying properties for
that neighbor:
.Bd -literal -offset indent
neighbor 10.0.0.2 {
	remote-as 65002
	descr "a neighbor"
}
.Ed
.Pp
Multiple neighbors can be grouped together by a group section.
Each neighbor statement within the group section inherits all properties
from the group section.
.Bd -literal -offset indent
group "peering AS65002" {
	remote-as 65002
	neighbor 10.0.0.2 {
		descr "AS65002-p1"
	}
	neighbor 10.0.0.3 {
		descr "AS65002-p2"
	}
}
.Ed
.Pp
There are several neighbor properties:
.Bl -tag -width xxxxxxxx
.It Ar remote-as
Set the AS number of the remote system.
.It Ar descr
Add a description.
The description is used when logging neighbor events and in status
reports etc and has no further meaning to
.Ar bgpd .
.It Ar local-addr
When
.Ar bgpd
initiates the TCP connection to the neighbor system, it normally does not
bind to a specific IP address.
If a local-addr is given it binds
to this address before.
.It Ar multihop
Normally neighbors that are not in the same AS as the local
.Ar bgpd
have to be directly connected to the local machine.
If this is not the case the
.Em multihop
statement defines the maximum hops the neighbor is away.
.El
.Sh SEE ALSO
.Xr bgpd 8
.Sh FILES
.Bl -tag -width "/etc/bgpd.conf" -compact
.It Pa /etc/bgpd.conf
.Nm
configuration file.
.El
.Sh HISTORY
The
.Nm
program first appeared in
.Ox 3.5 .