Ignore ICMP Source Quench as a congestion-control signal

Keep this document to one review outcome: Ignore ICMP Source Quench as a congestion-control signal. Only the official source and traced locations below supply facts. Confirm applicability before acting.

Source fact:

The official RFC 6633 — Deprecation of ICMP Source Quench Messages from RFC Editor / Internet Engineering Task Force supports the following bounded statements:

• A host must not send ICMP Source Quench, and TCP must silently discard any Source Quench it receives. The research record locates this support at Section 3 (Updating RFC 1122).
• A router must ignore every received ICMP Source Quench message. The research record locates this support at Section 4 (Updating RFC 1812).
• UDP, SCTP, DCCP, and any other transport instance must silently ignore or discard a received Source Quench. The research record locates this support at Sections 5 (Clarification for UDP, SCTP, and DCCP) and 6 (General Advice to Transport Protocols).

Do not import neighboring assumptions into the source record. The supported task is a scoped comparison involving address plans, interfaces, routes, peers, protocol roles, timers, middleboxes, and intended failure domains and the conditions the source actually describes.

What the source does not establish

This RFC evidence supports only the named network-protocol decision; it does not select vendor settings, topology, capacity, or an acceptable failure mode. Do not read the source as proof of implementation or permission to change production. Its guidance remains conditional on DNS, Active Directory authentication, PKI, time, routing policy, transport reachability, and monitoring and the environment’s recorded constraints.

Applicability questions

• For source statement 1 at Section 3 (Updating RFC 1122), which observable configuration, record, or test can confirm applicability here?
• For source statement 2 at Section 4 (Updating RFC 1812), which observable configuration, record, or test can confirm applicability here?
• For source statement 3 at Sections 5 (Clarification for UDP, SCTP, and DCCP) and 6 (General Advice to Transport Protocols), which observable configuration, record, or test can confirm applicability here?
• Within address plans, interfaces, routes, peers, protocol roles, timers, middleboxes, and intended failure domains, which versions, roles, and configuration states define the review population?
• Could DNS, Active Directory authentication, PKI, time, routing policy, transport reachability, and monitoring invalidate the test, hide a failure, or change applicability?
• Who owns the decision, and which observation requires stopping, escalation, or rollback?

DSE recommendation:

DSE recommends using the cited source as the evidence anchor for this decision. Use a two-person review for the source interpretation and the resulting operational decision. Record the source location, examined part of address plans, interfaces, routes, peers, protocol roles, timers, middleboxes, and intended failure domains, observed and expected states, owner, and reason for deviation.

Translate the conclusion into change control only after documenting dependencies, impact, test method, expected signals, failure signals, and restoration steps. Include DNS, Active Directory authentication, PKI, time, routing policy, transport reachability, and monitoring, while excluding secrets and sensitive personal or topology data from ordinary tickets.

Verification and evidence

Tie each conclusion back to Section 3 (Updating RFC 1122); Section 4 (Updating RFC 1812); Sections 5 (Clarification for UDP, SCTP, and DCCP) and 6 (General Advice to Transport Protocols) and to observable material such as configuration snapshots, route or neighbor state, packet captures, counters, topology records, and controlled failover results. Preserve provenance and stable identifiers without copying secrets into the evidence set.

Retain the starting state, authorization, execution record, outcome, deviation, and final state as one review package. Move disruptive checks to an approved test path. Reopen the decision when versions, design, dependencies, ownership, or official guidance changes.

Official references

• RFC 6633 — Deprecation of ICMP Source Quench Messages — RFC Editor / Internet Engineering Task Force