RFC 4459: MTU and Fragmentation Issues with In-the-Network Tunneling

Publisher

RFC Editor (IETF)

URL

https://www.rfc-editor.org/rfc/rfc4459.html

Published

2006-04-01

Updated

unknown

Accessed

2026-10-02

HTTP status

200

License

IETF Trust Legal Provisions; no-redistribution; short excerpts and locators only

Source notes citing this source

• RFC 4459 says PMTUD signalling for tunnels is unreliable in IPv4 because firewalls and other boxes are often configured to drop all ICMP. in context
• RFC 4459 describes how tunnelling (IP-in-IP, GRE, L2TP, IPsec) adds encapsulation headers, so a source must size packets to fit the smallest MTU on the path after encapsulation. in context

Cite this source record

APA

WarmTransfer. (2006, April 1). RFC 4459: MTU and Fragmentation Issues with In-the-Network Tunneling. WarmTransfer. https://warmtransfer.net/knowledge/sources/rfc-4459-mtu-fragmentation-tunnels

BibTeX

@misc{warmtransfer-rfc-4459-mtu-fragmentation-tunnels,
  title  = {RFC 4459: MTU and Fragmentation Issues with In-the-Network Tunneling},
  author = {{WarmTransfer}},
  year   = {2006},
  url    = {https://warmtransfer.net/knowledge/sources/rfc-4459-mtu-fragmentation-tunnels},
  note   = {RFC Editor (IETF), accessed 2026-10-02}
}