EXABGP(1)

🦋 exabgp — NAME 🦋

okay so hi bestie, welcome to the manual page for exabgp (that's the <pink>exabgp(1)</pink> page, section 1, iykyk) and its whole entire vibe is: Influence or control network using BGP. that's it. that's the whole pitch. 💖

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🌸 SYNOPSIS 🌸

exabgp [--help | -h] [--version | -v] [--env env-config | -e env-config]
       [--full-ini | --fi] [--diff-ini | --di] [--full-env | --fe]
       [--diff-env | --de] [--debug | -d] [--signal time] [--once | -1]
       [--pdb | -p] [--memory | -s] [--profile profile] [--validate]
       [--test | -t] [--decode hex-message | -x hex-message]
       [configuration ...]

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💅 DESCRIPTION 💅

so exabgp lets engineers control their network from commodity servers. like, normal servers. not fancy router hardware. iconic behavior honestly. ✨

the ways people use it, fr fr:

• DDoS mitigation
• network visualisation
• service high availability
• implementing anycast

big important thing though bestie: exabgp does not perform any FIB manipulation on the system it runs on. if that's what you need, this is not the program for you. no cap. 🙈

and ALSO, exabgp can print received BGP messages into readable plain text or JSON formatted text. cute and useful, we love a dual threat. 💜

🎀 the arguments, one by one

• --env env-config | -e env-config — tell it where the environment configuration file can be found. 📁
• --full-env | --fe — print the full environment configuration on stdout, using the env format.
• --diff-env | --de — print only the non-default environment configuration on stdout, using the env format.
• --full-ini | --fi — print the full environment configuration used on stdout, using the ini format.
• --diff-ini | --di — print the non-default environment configuration on stdout, using the ini format.
• --debug | -d — start the python debugger on serious logging and on reception of the SIGTERM signal. this implies exabgp.log.all=true and exabgp.log.level=DEBUG. 🐛
• --signal time — issue a SIGUSR1 signal to reload the configuration after the specified number of seconds. only useful for code debugging, so don't be cute with it.
• --once | -1 — only perform one attempt to connect to peers. used mostly for debugging.
• --pdb | -p — start the python debugger on critical logging, reception of SIGTERM, and on uncaught python exceptions. this is a shortcut for exabgp.pdb.enable=true. 💀
• --memory | -s — display memory usage information on program exit.
• --profile profile — enable collection of profiling information to the given file. this is a shortcut for exabgp.profile.enable=true and exabgp.profile.file=profile.
• --test | -t — only do a configuration validity check. nothing else, just the vibe check. ✅
• --validate — validate the configuration file format only.
• --decode hex-message | -x hex-message — decode a raw route packet in hexadecimal string.
• --help | -h — display summary of usage and configuration of exabgp.
• --version | -v — display the exabgp version number and exit. 🫶

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🌈 ENVIRONMENT 🌈

okay so the configuration of exabgp is split in two, bestie, keep up:

• the environment configuration, which controls the basic execution of exabgp such as logging, daemonizing, pid-file, profiling etc.
• the BGP configuration of exabgp, which specifies which neighbors it should talk BGP with and all other aspects of the BGP configuration.

🧚 how you can set the environment config (priority order, lowkey important)

you can specify the environment configuration a number of different ways, and they have different priority:

1. Command line values using dot-separated notation.
2. Environment variables using dot-separated notation.
3. Command line values using underscore-separated notation.
4. Environment variables using underscore-separated notation.
5. The values from the ini configuration file, /etc/exabgp/exabgp.env
6. The built-in default values.

so yeah, number 1 wins over everything, and number 6 is the fallback when nobody else showed up to the party. periodt.

💖 the environment variables (all of them, no skipping, we don't do that here)

• exabgp.api.ack — Acknowledge api commands and report issues. Default: true.
• exabgp.api.chunk — Maximum number of lines to print before yielding in "show routes" api. Default: 1.
• exabgp.api.cli — Determines if exabgp should create a named pipe for the CLI. Default: true.
• exabgp.api.compact — Determines whether exabgp should use shorter JSON encoding for IPv4/IPv6 unicast NLRI. Default: false.
• exabgp.api.encoder — (experimental) default encoder to use with external API (text or json). Default: text.
• exabgp.api.pipename — Base name to be used for the exabgp pipe for the CLI interface. Default: exabgp.
• exabgp.api.respawn — Controls whether to respawn a helper process if it dies. Default: false.
• exabgp.api.terminate — Controls whether to exit if any helper process dies. Default: false.
• exabgp.bgp.openwait — Controls how many seconds we should wait for a BGP open message once the TCP session is established. Default: 60 seconds.
• exabgp.cache.attributes — Controls whether all attributes (configuration and wire) should be cached for faster parsing. Default: true.
• exabgp.cache.nexthops — (deprecated, next-hops are always cached) Default: true.
• exabgp.daemon.daemonize — Controls whether exabgp should run in the background. Default: false.
• exabgp.daemon.drop — Determines if exabgp should drop privileges before forking processes. Default: true.
• exabgp.daemon.pid — Where to save the PID of exabgp if we manage it. Default: '' (not set).
• exabgp.daemon.umask — Controls umask to set, controls permissions of created files, e.g. logs. Default: 0137.
• exabgp.daemon.user — The user to run exabgp as. Should be an unprivileged user. Default: nobody.
• exabgp.log.all — Controls whether debug logging should be done for everything. Default: false.
• exabgp.log.configuration — Controls whether logging should be done for the configuration and command parsing. Default: true.
• exabgp.log.daemon — Controls whether logging should be done for PID change, forking, etc. Default: true.
• exabgp.log.destination — Controls where logging should be sent. syslog (or no setting) sends the data to the local syslog server with the LOG_DAEMON facility (used to be LOG_USER). host:<location> sends the data to a remote syslog server. stdout sends the data to stdout. stderr sends the data to stderr. <filename> sends the data to the named file. Default: stdout.
• exabgp.log.enable — Controls whether logging should be done. Default: true.
• exabgp.log.level — Sets the minimum severity level to log. Default: INFO.
• exabgp.log.message — Controls logging of changes in route announcement in config reload. Default: false.
• exabgp.log.network — Controls logging of networking information (TCP/IP state, network state etc.). Default: true.
• exabgp.log.statistics — Controls logging of packet statistics (counters). Default: true.
• exabgp.log.packets — Controls logging of BGP packets sent and received. Default: false.
• exabgp.log.parser — Controls logging of BGP message parsing details. Default: false.
• exabgp.log.processes — Controls logging of forked processes. Default: true.
• exabgp.log.reactor — Controls logging of signals received and command reload. Default: true.
• exabgp.log.rib — Controls logging of changes in locally configured routes. Default: false.
• exabgp.log.routes — Controls logging of received routes. Default: false.
• exabgp.log.short — Controls whether to use long or short log format (not prepended with time, level, pid and source). Default: false.
• exabgp.log.timers — Controls logging of keepalive timers. Default: false.
• exabgp.pdb.enable — Controls whether pdb, the python interactive debugger should be started on program faults. Default: false.
• exabgp.profile.enable — Controls whether profiling of the code should be done. Default: false.
• exabgp.profile.file — Controls where profiling results should be written. None/empty means stdout. Default: empty.
• exabgp.reactor.speed — Controls the time of one reactor loop. Use only if you understand the code. Default: 1.0.
• exabgp.tcp.acl — (experimental, unimplemented). Default: empty.
• exabgp.tcp.bind — List of IP addresses to bind to when listening (no ip to disable). Default: empty.
• exabgp.tcp.delay — Start to announce routes when the minutes in the hour is a modulo of this number. Default: 0.
• exabgp.tcp.once — Only perform one TCP connection attempt per peer, for debugging scripts. Default: false.
• exabgp.tcp.port — Port to bind to when listening. Default: 179.

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🎀 FILES 🎀

/etc/exabgp/exabgp.env is the default file for setting the "environment" variables controlling the execution of exabgp. an alternative "env" configuration file can be supplied via the --env env-config argument. 📂

the format of this file is "Windows INI format". all the default settings can be shown with the exabgp --test --full-init command, and an example showing parts of this output is:

[exabgp.api]
encoder = text
respawn = false

[exabgp.bgp]
openwait = 60

additionally, the user will need to supply a configuration file controlling the BGP configuration of exabgp, in the format described in exabgp.conf(5). don't forget bestie, both files, both vibes. 🦋

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👑 SIGNALS 👑

exabgp catches a few different signals to control specific actions. they are, in no particular order of drama:

• ALRM — Restarts exabgp.
• USR1 — Causes exabgp to reload the configuration.
• USR2 — Causes exabgp to reload the configuration and restart any forked processes.
• TERM — Terminates exabgp.
• HUP — Also terminates exabgp (does not reload the configuration anymore).

lowkey a warning bestie: reloading large configurations using signals is currently not recommended, because the configuration parsing code is currently blocking. therefore if you have a large configuration change, it could cause the peer to miss some keepalive and cause a session flap. 😭 that's not the slay we're going for.

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✨ DIAGNOSTICS ✨

okay so bestie, if you wanna make sure your config file isn't about to cause a syntax-error meltdown, the --test argument is literally there to validate the syntax of the configuration file. it's giving vibe check but for configs, and it ate. 💅

And the --debug flag? It will provide copious debug output — like, copious copious — to wherever the various exabgp.log variable settings dictate. So it's not just a little sprinkle, it's the whole glitter cannon. 🎀

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🌈 SEE ALSO 🌈

• exabgp.conf(5) — the other manual page you need in your life. Go read it, bestie. iykyk. 💖

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👑 STANDARDS 👑

A list of the standards exabgp implements which is indicative of the features implemented is:

• RFC 4893 — BGP Support for Four-octet AS Number Space
• RFC 4760 — Multiprotocol Extension for BGP-4
• RFC 4659 — BGP-MPLS IP Virtual Private Network (VPN) Extension for IPv6 VPN
• RFC 4762 — Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signalling
• RFC 5575 — Dissemination of Flow Specification Rules
• RFC 4724 — Graceful Restart Mechanism for BGP
• RFC 7313 — Enhanced Route Refresh Capability for BGP-4
• RFC 7311 — The Accumulated IGP Metric Attribute for BGP
• draft-raszuk-idr-flow-spec-v6-03 (draft-ietf-idr-flow-spec-v6-06) — Dissemination of Flow Specification Rules for IPv6
• draft-simpson-idr-flowspec-redirect-00 (-02) — BGP Flow-Spec Redirect to IP Action
• draft-ietf-idr-flowspec-redirect-00 (-02) — BGP Flow-Spec Redirect to IP Action
• draft-ietf-idr-add-paths-08 (-10) — Advertisement of Multiple Paths in BGP
• draft-ietf-idr-bgp-multisession-07 (??)
• draft-scudder-bmp-01 (??)

A list of other more basic BGP-related standard entirely or partially implemented is:

• RFC 1997 — BGP Communities Attribute
• RFC 8092 — BGP Large Communities Attribute
• RFC 2385 — Protection of BGP Sessions via the TCP MD5 Signature
• RFC 2545 — Use of BGP-4 Multiprotocol Extensions for IPv6 Inter-Domain Routing
• RFC 2918 — Route Refresh Capability for BGP-4
• RFC 3107 — Carrying Label Information in BGP-4
• RFC 3765 — NOPEER Community for Border Gateway Protocol (BGP) Route Scope Control
• RFC 7999 — BLACKHOLE BGP Community for Blackholing
• RFC 4271 — A Border Gateway Protocol 4 (BGP-4)
• RFC 4360 — BGP Extended Communities Attribute
• RFC 4364 — Constrained Route Distribution for BGP/MPLS IP VPNs
• RFC 4456 — BGP Route Reflection: An Alternative to Full Mesh Internal BGP (iBGP)
• RFC 5396 — Textual Representation of Autonomous System (AS) Numbers
• RFC 5492 — Capabilities Advertisement with BGP-4
• RFC 6286 — Autonomous-System-Wide Unique BGP Identifier for BGP-4
• RFC 6608 — Subcodes for BGP Finite State Machine Error
• RFC 7752 — North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP
• draft-gredler-idr-bgp-ls-segment-routing-ext-03 — BGP Link-State extensions for Segment Routing
• draft-ietf-idr-bgp-prefix-sid-05 — Segment Routing Prefix SID extensions for BGP

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And that's the whole thing, bestie. This iconic page is EXABGP(1), dated October 14, 2022. slay, bye. 💖✨🦋