...
A user-space implementation over UDP is included in the VFER bulk transfer tool.
Minimum Path MTU Hop-by-Hop Option
Recently, the IETF 6man Working Group has adopted an Internet-Draft (see reference below) proposing an IPv6 hop-by-hop option that would allow discovering the Path MTU with assistance from routers. Note that this still requires a mechanism to "echo" the discovered PMTU back to the sender.
References
- RFC 4821, Packetization Layer Path MTU Discovery, M. Mathis, J. Heffner, March 2007.
- RFC 1191, Path MTU discovery, Mogul, J. and S. Deering, November 1990.
- RFC 1981, Path MTU Discovery for IP version 6, McCann, J., Deering, S., and J. Mogul, August 1996.
- draft-ietf-6man-rfc1981bis-06, Path MTU Discovery for IP version 6, Jack McCann, Stephen E. Deering, Jeffrey Mogul, Robert M. Hinden, April 2017
- RFC 2923, TCP Problems with Path MTU Discovery, K. Lahey, September 2000
- RFC 3128, Protection Against a Variant of the Tiny Fragment Attack (RFC 1858), Miller, I., June 2001.
- RFC 4459, MTU and Fragmentation Issues with In-the-Network Tunneling, P. Savola, February 2006.
- draft-saum-nvo3-pmtud-over-vxlan-05, PMTUD Over Vxlan, Saumya Dikshit, A Sujeet Nayak, June 2017
- Measuring the Evolution of Transport Protocols in the Internet, A. Medina, M. Allman, and S. Floyd, April 2005.
- PMTU (Path MTU) Discovery - Some servers are unusable for many internet users, an article about problems with Path MTU Discovery and their effects.
- Practical hints from Cisco for working around PMTUD issues, for Windows, Solaris, and other systems
- IP Fragmentation and PMTUD, Cisco White Paper
- draft-ietf-tsvwg-datagram-plpmtud-0708, Packetization Layer Path MTU Discovery for Datagram Transports, Godred Fairhurst, Tom Jones, Michael Tuexen, Irene Ruengeler, Timo Voelker, February June 2019
- draft-fairhurst-tsvwg-udp-options-dplpmtud-00, Datagram PLPMTUD for UDP Options, Godred Fairhurst, Tom Jones, April 2019
- draft-venaasietf-bier-path-mtu-mtuddiscovery-02, BIER MTU Discovery, Stig Venaas, IJsbrand Wijnands, Les Ginsberg, Mahesh Sivakumar, October 201806, Path Maximum Transmission Unit Discovery (PMTUD) for Bit Index Explicit Replication (BIER) Layer, Greg Mirsky, Tony Przygienda, Andrew Dolganow, June 2019
- draft-ietf-tram-stun-pmtud-12, Path MTU Discovery Using Session Traversal Utilities for NAT (STUN), Marc Petit-Huguenin, Gonzalo Salgueiro, Felipe Garrido, September 2019
- draft-ietf-6man-mtu-option-00, IPv6 Minimum Path MTU Hop-by-Hop Option, Robert M. Hinden, Godred Fairhurst, August 2019
Implementations
- for Linux 2.6 - integrated in mainstream kernel as of 2.6.17. However, it is disabled by default (see net.ipv4.tcp_mtu_probing sysctl)
- for NetBSD
-- HankNussbacher - 2005-07-03
– SimonLeinen - 2006-07-19 - 2019-0409-2710