Network Working Group D. Abraitis
Internet-Draft Hostinger
Intended status: Informational December 1, 2019
Expires: June 3, 2020

Version Capability for BGP


In this document, we introduce a new BGP capability that allows the advertisement of a BGP speaker's version.

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Table of Contents

1. Introduction

In modern data center designs, we tend to have conventional hosts participating in the routing process. And the fleet of hosts has different versions of routing daemon. This means that troubleshooting is a crucial part to quickly identify the root cause. This document introduces new BGP capability to advertise the version of routing daemon.

2. Specification of Requirements

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

3. Version Capability

The Version Capability is a new BGP capability [RFC5492]. The implementation is specific to the vendor. The version is unstructured and can be defined in any format the vendor decides.

                |    Version Length (1 octet)    |
                |      Version (variable)        |

Figure 1

Version Length:


4. Operation

The Version capability MUST only be used for displaying the version of a speaker in order to make troubleshooting easier. You have a bunch of routers with a number of upstreams each. All of them are with a different operating system and routing daemon installed. Assuming that a specific feature is not working or a bug which is not fixed in an appropriate version, would allow us to quickly identify the pattern which versions are affected. Below is an example of implementation in [FRRouting] how it looks like with version advertised by a BGP sender:

:~# vtysh -c 'show ip bgp neighbors json' \
> | jq '."".neighborCapabilities.versions'
  "advertisedVersion": "FRRouting 7.2-dev-MyOwnFRRVersion",
  "receivedVersion": "FRRouting 7.2-dev-MyOwnFRRVersion-gc68bb14"

Figure 2

5. IANA Considerations

IANA maintains the "Border Gateway Protocol (BGP) Parameters" registry with a subregistry called "Capabilities Codes". IANA is requested to assign a capability number from the First Come First Served range for the Version Capability in this document as follows:

Version Capability
Value Description Reference
TBD Version Capability [draft-abraitis-bgp-version-capability]

6. Security Considerations

The Version Capability can be treated as sensitive information, thus it would be easier for an attacker to exploit by knowing the specific version of the BGP speaker. This information can be gathered in BGP OPEN messages.

The Version Capability MUST be configurable with a vendor-specific knob to be able to enable or disable the capability. The vendor might implement to disable this capability per neighbor.

It would be safe to enable this for iBGP or inside the same tenant where you have full control and the BGP speaker is behind exit points.

The Version Capability information can be gathered in BGP OPEN messages.

Modifying the information advertised by a router might lead to attacks including bogus software upgrades and also might mask the causes of faults in the network.

Advertising which versions of code and from which vendor it comes may facilitate a number of social-engineering attacks.

Sensitive information leaks can be minimized by using the [RFC5082] mechanism or firewalls to filter out TCP 179 port from untrusted networks. This capability can be disabled per neighbor, thus the sensitive information can't be disclosed to untrusted neighbors.

7. References

7.1. Normative References

[FRRouting] Abraitis, D., "FRRouting - BGP Version Capability", 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.

7.2. Informative References

[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC Text on Security Considerations", BCP 72, RFC 3552, DOI 10.17487/RFC3552, July 2003.

Author's Address

Donatas Abraitis Hostinger Jonavos g. 60C Kaunas, 44192 LT Phone: +370 614 18958 EMail: