Source note · SIP ALG problems on firewalls and routers
RFC 4787 (BCP 127) REQ-10 states that NAT ALGs for UDP-based protocols SHOULD be turned off, so that they do not interfere with UNSAF NAT traversal mechanisms and so that integrity protection of UDP communications is possible.
Checked 2026-09-25
NAT ALGs for UDP-based protocols SHOULD be turned off.
- Vendor
- IETF
- Product
- NAT devices
- Subsystem
- NAT behaviour
- Deployment
- on-premises, multi-tenant, hybrid
- Region
- not restricted
- Release range
- BCP 127 January 2007
- Checked
- 2026-09-25
Sources
- RFC 4787: Network Address Translation (NAT) Behavioral Requirements for Unicast UDP (BCP 127) — IETF / RFC Editor · tier 1 standards and regulators · Section 7 REQ-10
Cite this note
APA
WarmTransfer. (2026, September 25). SIP ALG problems on firewalls and routers: source note sip-alg-problems-rfc4787-alg-should-be-off. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-alg-problems-rfc4787-alg-should-be-off
BibTeX
@misc{warmtransfer-claim-sip-alg-problems-rfc4787-alg-should-be-off,
title = {SIP ALG problems on firewalls and routers: source note sip-alg-problems-rfc4787-alg-should-be-off},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-alg-problems-rfc4787-alg-should-be-off},
note = {Source note sip-alg-problems-rfc4787-alg-should-be-off, checked 2026-09-25}
}