BGPD.CONF(5)              OpenBSD Programmer's Manual             BGPD.CONF(5)

NAME
     bgpd.conf - Border Gateway Protocol daemon configuration file

DESCRIPTION
     The bgpd(8) daemon implements the Border Gateway Protocol version 4 as
     described in RFC 1771.

SECTIONS
     The bgpd.conf config file is divided into four main sections.

     Macros
           User-defined variables may be defined and used later, simplifying
           the configuration file.

     Global Configuration
           Global settings for bgpd(8).

     Neighbors and Groups
           bgpd(8) establishes sessions with neighbors.  The neighbor defini-
           tion and properties are set in this section, as well as grouping
           neighbors for the ease of configuration.

     Filter
           Filter rules for incoming and outgoing UPDATES.

     With the exception of macros, the sections should be grouped and appear
     in bgpd.conf in the order shown above.

     Comments can be put anywhere in the file using a hash mark (`#'), and ex-
     tend to the end of the current line.

     Additional configuration files can be included with the include keyword,
     for example:

           include "/etc/bgpd/bgpd-10.0.0.1.filter"

MACROS
     Macros can be defined that will later be expanded in context.  Macro
     names must start with a letter, and may contain letters, digits and un-
     derscores.  Macro names may not be reserved words (for example, AS,
     neighbor, or group).  Macros are not expanded inside quotes.

     For example:

           peer1="1.2.3.4"
           neighbor $peer1 {
                   remote-as 65001
           }

GLOBAL CONFIGURATION
     There are quite a few settings that affect the operation of the bgpd(8)
     daemon globally.

     AS as-number [as-number]
             Set the local autonomous system number to as-number.  If the
             first AS number is a 4-byte AS it is possible to specify a sec-
             ondary 2-byte AS number which is used for neighbors which do not
             support 4-byte AS numbers.  The default for the secondary AS is
             23456.

             The AS numbers are assigned by local RIRs, such as:

             AfriNIC   for Africa
             APNIC     for Asia Pacific
             ARIN      for North America and parts of the Caribbean
             LACNIC    for Latin America and the Caribbean
             RIPE NCC  for Europe, the Middle East, and parts of Asia

             For example:

                   AS 65001

             sets the local AS to 65001.

             The AS numbers 64512 - 65534 are designated for private use.  The
             AS number 23456 is a specially designated Autonomous System Num-
             ber and should not be used.  4-byte AS numbers are specified as
             two numbers separated by a dot (ASDOT format), for example:

                   AS 3.10

             or as a large number (ASPLAIN format), for example:

                   AS 196618

     connect-retry seconds
             Set the number of seconds before retrying to open a connection.
             This timer should be sufficiently large in EBGP configurations.
             The default is 120 seconds.

     dump [rib name] (table|table-mp) file [timeout]
     dump (all|updates) (in|out) file [timeout]
             Dump the RIB, a.k.a. the routing information base, and all BGP
             messages in Multi-threaded Routing Toolkit (MRT) format.  Dumping
             the RIB is normally an expensive operation, but it should not in-
             fluence the session handling.  It is possible to dump alternate
             RIB with the use of name.

             For example, the following will dump the entire table to the
             strftime(3)-expanded filename.  The table-mp format is multi-pro-
             tocol capable but often not supported by 3rd-party tools.  The
             timeout is optional:

                   dump table "/tmp/rib-dump-%H%M" 300

             Similar to the table dump, but this time all BGP messages and
             state transitions will be dumped to the specified file:

                   dump all in "/tmp/all-in-%H%M" 300

             As before, but only the UPDATE messages will be dumped to the
             file:

                   dump updates in "/tmp/updates-in-%H%M" 300

             It is also possible to dump outgoing messages:

                   dump all out "/tmp/all-out-%H%M" 300
                   # or
                   dump updates out "/tmp/updates-out-%H%M" 300

     fib-update (yes|no)
             If set to no, do not update the Forwarding Information Base,
             a.k.a. the kernel routing table.  The default is yes.

     holdtime seconds
             Set the holdtime in seconds.  The holdtime is reset to its ini-
             tial value every time either a KEEPALIVE or an UPDATE message is
             received from the neighbor.  If the holdtime expires the session
             is dropped.  The default is 90 seconds.  Neighboring systems ne-
             gotiate the holdtime used when the connection is established in
             the OPEN messages.  Each neighbor announces its configured hold-
             time; the smaller one is then agreed upon.

     holdtime min seconds
             The minimal accepted holdtime in seconds.  This value must be
             greater than or equal to 3.

     listen on address
             Specify the local IP address bgpd(8) should listen on.

                   listen on 127.0.0.1

     log updates
             Log received and sent updates.

     network address/prefix [set ...]
     network (inet|inet6) static [set ...]
     network (inet|inet6) connected [set ...]
             Announce the specified network as belonging to our AS.  If set to
             connected, routes to directly attached networks will be an-
             nounced.  If set to static, all static routes will be announced.

                   network 192.168.7.0/24

             It is possible to set default AS path attributes per network
             statement:

                   network 192.168.7.0/24 set localpref 220

             See also the ATTRIBUTE SET section.

     nexthop qualify via (bgp|default)
             If set to bgp, bgpd(8) may use BGP routes to verify nexthops.  If
             set to default, bgpd may use the default route to verify nex-
             thops.  By default bgpd will only use static routes or routes
             added by other routing daemons like ospfd(8).

     rde med compare (always|strict)
             If set to always, the MED attributes will always be compared.
             The default is strict, where the MED is only compared between
             peers belonging to the same AS.

     rde rib name [no evaluate]
             Create an additional RIB named name.  It is possible to disable
             the decision process per RIB with the no evaluate flag.  Adj-RIB-
             In and Loc-RIB are created automatically and used as default.

     rde route-age (ignore|evaluate)
             If set to evaluate, the best path selection will not only be
             based on the path attributes but also on the age of the route,
             giving preference to the older, typically more stable, route.  In
             this case the decision process is no longer deterministic.  The
             default is ignore.

     route-collector (yes|no)
             If set to yes, the route selection process is turned off.  The
             default is no.

     router-id address
             Set the router ID to the given IP address, which must be local to
             the machine.

                   router-id 10.0.0.1

             If not given, the BGP ID is determined as the biggest IP address
             assigned to the local machine.

     rtable number
             Work with the given kernel routing table instead of the default
             table, 0.  Note that this table is used for nexthop verification
             as well.  Directly connected networks are always taken into ac-
             count, even though their routes live in table 0.

     transparent-as (yes|no)
             If set to yes, AS paths to EBGP neighbors are not prepended with
             their own AS.  The default is no.

NEIGHBORS AND GROUPS
     bgpd(8) establishes TCP connections to other BGP speakers called
     neighbors.  Each neighbor is specified by a neighbor section, which al-
     lows properties to be set specifically for that neighbor:

           neighbor 10.0.0.2 {
                   remote-as 65002
                   descr "a neighbor"
           }

     Multiple neighbors can be grouped together by a group section.  Each
     neighbor section within the group section inherits all properties from
     its group:

           group "peering AS65002" {
                   remote-as 65002
                   neighbor 10.0.0.2 {
                           descr "AS65002-p1"
                   }
                   neighbor 10.0.0.3 {
                           descr "AS65002-p2"
                   }
           }

     Instead of the neighbor's IP address, an address/netmask pair may be giv-
     en:

           neighbor 10.0.0.0/8

     In this case, the neighbor specification becomes a template, and if a
     neighbor connects from an IP address within the given network, the tem-
     plate is cloned, inheriting everything from the template but the remote
     address, which is replaced by the connecting neighbor's address.  With a
     template specification it is valid to omit remote-as; bgpd(8) will then
     accept any AS the neighbor presents in the OPEN message.

     There are several neighbor properties:

     announce (all|none|self|default-route)
             If set to none, no UPDATE messages will be sent to the neighbor.
             If set to default-route, only the default route will be announced
             to the neighbor.  If set to all, all generated UPDATE messages
             will be sent to the neighbor.  This is usually used for transit
             AS's and IBGP peers.  The default value for EBGP peers is self,
             which limits the sent UPDATE messages to announcements of the lo-
             cal AS.  The default for IBGP peers is all.

     announce (IPv4|IPv6) (none|unicast)
             For the given address family, control which subsequent address
             families (at the moment, only none, which disables the announce-
             ment of that address family, and unicast are supported) are an-
             nounced during the capabilities negotiation.  Only routes for
             that address family and subsequent address family will be an-
             nounced and processed.

     announce as-4byte (yes|no)
             If set to no, the 4-byte AS capability is not announced and so
             native 4-byte AS support is disabled.  The default is yes.

     announce capabilities (yes|no)
             If set to no, capability negotiation is disabled during the es-
             tablishment of the session.  This can be helpful to connect to
             old or broken BGP implementations.  The default is yes.

     announce refresh (yes|no)
             If set to no, the route refresh capability is not announced.  The
             default is yes.

     announce restart (yes|no)
             If set to yes, the graceful restart capability is announced.
             Currently only the End-of-RIB marker is supported and announced
             by the restart capability.  The default is no.

     demote group
             Increase the carp(4) demotion counter on the given interface
             group, usually carp, when the session is not in state
             ESTABLISHED.  The demotion counter will be increased as soon as
             bgpd(8) starts and decreased 60 seconds after the session went to
             state ESTABLISHED.  For neighbors added at runtime, the demotion
             counter is only increased after the session has been ESTABLISHED
             at least once before dropping.

             For more information on interface groups, see the group keyword
             in ifconfig(8).

     depend on interface
             The neighbor session will be kept in state IDLE as long as
             interface reports no link.  For carp(4) interfaces, no link means
             that the interface is currently backup.  This is primarily in-
             tended to be used with carp(4) to reduce failover times.

             The state of the network interfaces on the system can be viewed
             using the show interfaces command to bgpctl(8).

     descr description
             Add a description.  The description is used when logging neighbor
             events, in status reports, for specifying neighbors, etc., but
             has no further meaning to bgpd(8).

     down    Do not start the session when bgpd comes up but stay in IDLE.

     dump (all|updates) (in|out) file [timeout]
             Do a peer specific MRT dump.  Peer specific dumps are limited to
             all and updates.  See also the dump section in GLOBAL
             CONFIGURATION.

     enforce neighbor-as (yes|no)
             If set to yes, AS paths whose leftmost AS is not equal to the
             remote AS of the neighbor are rejected and a NOTIFICATION is sent
             back.  The default value for IBGP peers is no otherwise the de-
             fault is yes.

     holdtime seconds
             Set the holdtime in seconds.  Inherited from the global configu-
             ration if not given.

     holdtime min seconds
             Set the minimal acceptable holdtime.  Inherited from the global
             configuration if not given.

     ipsec (ah|esp) (in|out) spi spi-number authspec [encspec]
             Enable IPsec with static keying.  There must be at least two
             ipsec statements per peer with manual keying, one per direction.
             authspec specifies the authentication algorithm and key.  It can
             be

                   sha1 <key>
                   md5 <key>

             encspec specifies the encryption algorithm and key.  ah does not
             support encryption.  With esp, encryption is optional.  encspec
             can be

                   3des <key>
                   3des-cbc <key>
                   aes <key>
                   aes-128-cbc <key>

             Keys must be given in hexadecimal format.

     ipsec (ah|esp) ike
             Enable IPsec with dynamic keying.  In this mode, bgpd(8) sets up
             the flows, and a key management daemon such as isakmpd(8) is re-
             sponsible for managing the session keys.  With isakmpd(8), it is
             sufficient to copy the peer's public key, found in
             /etc/isakmpd/local.pub, to the local machine.  It must be stored
             in a file named after the peer's IP address and must be stored in
             /etc/isakmpd/pubkeys/ipv4/.  The local public key must be copied
             to the peer in the same way.  As bgpd(8) manages the flows on its
             own, it is sufficient to restrict isakmpd(8) to only take care of
             keying by specifying the flags -Ka.  This can be done in
             rc.conf.local(8).  After starting the isakmpd(8) and bgpd(8) dae-
             mons on both sides, the session should be established.

     local-address address
             When bgpd(8) initiates the TCP connection to the neighbor system,
             it normally does not bind to a specific IP address.  If a local-
             address is given, bgpd(8) binds to this address first.

     max-prefix number [restart number]
             Terminate the session after number prefixes have been received
             (no such limit is imposed by default).  If restart is specified,
             the session will be restarted after number minutes.

     multihop hops
             Neighbors not in the same AS as the local bgpd(8) normally have
             to be directly connected to the local machine.  If this is not
             the case, the multihop statement defines the maximum hops the
             neighbor may be away.

     passive
             Do not attempt to actively open a TCP connection to the neighbor
             system.

     remote-as as-number
             Set the AS number of the remote system.

     rib name
             Bind the neighbor to the specified RIB.

     route-reflector [address]
             Act as an RFC 2796 route-reflector for this neighbor.  An option-
             al cluster ID can be specified; otherwise the BGP ID will be
             used.

     set attribute ...
             Set the AS path attributes to some default per neighbor or group
             block:

                   set localpref 300

             See also the ATTRIBUTE SET section.  Set parameters are applied
             to the received prefixes; the only exceptions are prepend-self,
             nexthop no-modify and nexthop self.  These sets are rewritten in-
             to filter rules and can be viewed with ``bgpd -nv''.

     softreconfig (in|out) (yes|no)
             Turn soft reconfiguration on or off for the specified direction.
             If soft reconfiguration is turned on, filter changes will be ap-
             plied on configuration reloads.  If turned off, a BGP session
             needs to be cleared to apply the filter changes.  Enabling
             softreconfig in will raise the memory requirements of bgpd(8) be-
             cause the unmodified AS path attributes need to be stored as
             well.  The default is yes.

     tcp md5sig password secret
     tcp md5sig key secret
             Enable TCP MD5 signatures per RFC 2385.  The shared secret can
             either be given as a password or hexadecimal key.

                   tcp md5sig password mekmidasdigoat
                   tcp md5sig key deadbeef

     transparent-as (yes|no)
             If set to yes, AS paths to EBGP neighbors are not prepended with
             their own AS.  The default is inherited from the global
             transparent-as setting.

     ttl-security (yes|no)
             Enable or disable ttl-security.  When enabled, outgoing packets
             are sent using a TTL of 255 and a check is made against an incom-
             ing packet's TTL.  For directly connected peers, incoming packets
             are required to have a TTL of 255, ensuring they have not been
             routed.  For multihop peers, incoming packets are required to
             have a TTL of 256 minus multihop distance, ensuring they have not
             passed through more than the expected number of hops.  The de-
             fault is no.

FILTER
     bgpd(8) has the ability to allow and deny UPDATES based on prefix or AS
     path attributes.  In addition, UPDATES may also be modified by filter
     rules.

     For each UPDATE processed by the filter, the filter rules are evaluated
     in sequential order, from first to last.  The last matching allow or deny
     rule decides what action is taken.

     The following actions can be used in the filter:

     allow     The UPDATE is passed.

     deny      The UPDATE is blocked.

     match     Apply the filter attribute set without influencing the filter
               decision.

PARAMETERS
     The rule parameters specify the UPDATES to which a rule applies.  An
     UPDATE always comes from, or goes to, one neighbor.  Most parameters are
     optional, but each can appear at most once per rule.  If a parameter is
     specified, the rule only applies to packets with matching attributes.

     as-type as-number
             This rule applies only to UPDATES where the AS path matches.  The
             as-number is matched against a part of the AS path specified by
             the as-type.  as-type is one of the following operators:

             AS           (any part)
             peer-as      (leftmost AS number)
             source-as    (rightmost AS number)
             transit-as   (all but the rightmost AS number)

             Multiple as-number entries for a given type or as-type as-number
             entries may also be specified, separated by commas or whitespace,
             if enclosed in curly brackets:

                   deny from any AS { 1, 2, 3 }
                   deny from any { AS 1, source-as 2, transit-as 3 }
                   deny from any { AS { 1, 2, 3 }, source-as 4, transit-as 5 }

     community as-number:local
     community name
             This rule applies only to UPDATES where the community path at-
             tribute is present and matches.  Communities are specified as as-
             number:local, where as-number is an AS number and local is a lo-
             cally significant number between zero and 65535.  Both as-number
             and local may be set to `*' to do wildcard matching.  Alterna-
             tively, well-known communities may be given by name instead and
             include NO_EXPORT, NO_ADVERTISE, NO_EXPORT_SUBCONFED, and
             NO_PEER.  Both as-number and local may be set to neighbor-as,
             which is expanded to the current neighbor remote AS number.

     ext-community subtype as-number:local
     ext-community subtype IP:local
     ext-community subtype numvalue
             This rule applies only to UPDATES where the extended community
             path attribute is present and matches.  Extended Communities are
             specified by a subtype and normally two values, a globally unique
             part (e.g. the AS number) and a local part.  See also the
             ATTRIBUTE SET section for further information about the encoding.

     (from|to) peer
             This rule applies only to UPDATES coming from, or going to, this
             particular neighbor.  This parameter must be specified.  peer is
             one of the following:

             any          Any neighbor will be matched.
             address      Neighbors with this address will be matched.
             group descr  Neighbors in this group will be matched.

             Multiple peer entries may also be specified, separated by commas
             or whitespace, if enclosed in curly brackets:

                   deny from { 128.251.16.1, 251.128.16.2, group hojo }

     (inet|inet6)
             This rule applies only to routes matching the stated address fam-
             ily.  The address family needs to be set only in rules that use
             prefixlen without specifying a prefix beforehand.

     prefix address/len
             This rule applies only to UPDATES for the specified prefix.

             Multiple address/len entries may be specified, separated by com-
             mas or whitespace, if enclosed in curly brackets:

                   deny from any prefix { 192.168.0.0/16, 10.0.0.0/8 }

             Multiple lists can also be specified, which is useful for macro
             expansion:

                   good="{ 192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8 }"
                   bad="{ 224.0.0.0/4, 240.0.0.0/4 }"
                   ugly="{ 127.0.0.1/8, 169.254.0.0/16 }"

                   deny from any prefix { $good $bad $ugly }

     prefixlen range
             This rule applies only to UPDATES for prefixes where the pre-
             fixlen matches.  Prefix length ranges are specified by using
             these operators:

                   =       (equal)
                   !=      (unequal)
                   <       (less than)
                   <=      (less than or equal)
                   >       (greater than)
                   >=      (greater than or equal)
                   -       (range including boundaries)
                   ><      (except range)

             >< and - are binary operators (they take two arguments).  For in-
             stance, to match all prefix lengths >= 8 and <= 12, and hence the
             CIDR netmasks 8, 9, 10, 11 and 12:

                   prefixlen 8-12

             Or, to match all prefix lengths < 8 or > 12, and hence the CIDR
             netmasks 0-7 and 13-32:

                   prefixlen 8><12

             prefixlen can be used together with prefix.

             This will match all prefixes in the 10.0.0.0/8 netblock with net-
             masks longer than 16:

                   prefix 10.0.0.0/8 prefixlen > 16

     quick   If an UPDATE matches a rule which has the quick option set, this
             rule is considered the last matching rule, and evaluation of sub-
             sequent rules is skipped.

     rib name
             Apply rule only to the specified RIB.  This only applies for re-
             ceived updates, so not for rules using the to peer parameter.

     set attribute ...
             All matching rules can set the AS path attributes to some de-
             fault.  The set of every matching rule is applied, not only the
             last matching one.  See also the following section.

ATTRIBUTE SET
     AS path attributes can be modified with set.

     set can be used on network statements, in neighbor or group blocks, and
     on filter rules.  Attribute sets can be expressed as lists.

     The following attributes can be modified:

     community [delete] as-number:local
     community [delete] name
             Set or delete the COMMUNITIES AS path attribute.  Communities are
             specified as as-number:local, where as-number is an AS number and
             local is a locally-significant number between zero and 65535.
             Alternately, well-known communities may be specified by name:
             NO_EXPORT, NO_ADVERTISE, NO_EXPORT_SUBCONFED, or NO_PEER.

     ext-community [delete] subtype as-number:local
     ext-community [delete] subtype IP:local
     ext-community [delete] subtype numvalue
             Set or delete the Extended Community AS path attribute.  Extended
             Communities are specified by a subtype and normally two values, a
             globally unique part (e.g. the AS number) and a local part.  The
             type is selected depending on the encoding of the global part.
             Two-octet AS Specific Extended Communities and Four-octet AS Spe-
             cific Extended Communities are encoded as as-number:local.  Four-
             octet encoding is used if the as-number is bigger then 65535 or
             if the AS_DOT encoding is used.  IPv4 Address Specific Extended
             Communities are encoded as IP:local.  Opaque Extended Communities
             are encoded with a single numeric value.  Currently the following
             subtypes are supported:

                   rt       Route Target
                   soo      Source of Origin
                   odi      OSPF Domain Identifier
                   ort      OSPF Route Type
                   ori      OSPF Router ID
                   bdc      BGP Data Collection

             Not all type and subtype value pairs are allowed by IANA and the
             parser will ensure that no invalid combination is created.

     localpref number
             Set the LOCAL_PREF AS path attribute.  If number starts with a
             plus or minus sign, LOCAL_PREF will be adjusted by adding or sub-
             tracting number; otherwise it will be set to number.  The default
             is 100.

     med number
     metric number
             Set the MULTI_EXIT_DISC AS path attribute.  If number starts with
             a plus or minus sign, MULTI_EXIT_DISC will be adjusted by adding
             or subtracting number; otherwise it will be set to number.

     origin (igp|egp|incomplete)
             Set the ORIGIN AS path attribute to mark the source of this route
             as being injected from an igp protocol, an egp protocol or being
             an aggregated route.

     nexthop (address|blackhole|reject|self|no-modify)
             Set the NEXTHOP AS path attribute to a different nexthop address
             or use blackhole or reject routes.  If set to no-modify, the nex-
             thop attribute is not modified.  Unless set to self, the nexthop
             is left unmodified for IBGP sessions.  self forces the nexthop to
             be set to the local interface address.

                   set nexthop 192.168.0.1
                   set nexthop blackhole
                   set nexthop reject
                   set nexthop no-modify
                   set nexthop self

     pftable table
             Add the prefix in the update to the specified pf(4) table, re-
             gardless of whether or not the path was selected for routing.
             This option may be useful in building realtime blacklists.

     prepend-neighbor number
             Prepend the neighbor's AS number times to the AS path.

     prepend-self number
             Prepend the local AS number times to the AS path.

     rtlabel label
             Add the prefix with the specified label to the kernel routing
             table.

     weight number
             The weight is used to tip prefixes with equally long AS paths in
             one or the other direction.  A prefix is weighed at a very late
             stage in the decision process.  If number starts with a plus or
             minus sign, the weight will be adjusted by adding or subtracting
             number; otherwise it will be set to number.  Weight is a local
             non-transitive attribute and a bgpd-specific extension.  For pre-
             fixes with equally long paths, the prefix with the larger weight
             is selected.

FILES
     /etc/bgpd.conf  bgpd(8) configuration file

SEE ALSO
     strftime(3), ipsec(4), pf(4), tcp(4), bgpctl(8), bgpd(8), ipsecctl(8),
     isakmpd(8), rc.conf.local(8)

HISTORY
     The bgpd.conf file format first appeared in OpenBSD 3.5.

OpenBSD 4.7                      March 5, 2010                              11
