In the SonicWall case, calls from external sources worked while some internal calls failed, because only the larger internal INVITEs were fragmented.

Checked 2026-10-02

Vendor
SonicWall
Product
SonicOS
Subsystem
VoIP inspection
Deployment
on-premises
Region
not restricted
Release range
SonicOS 5.8 and later per 2020 article
Checked
2026-10-02

Sources

Cite this note

APA

WarmTransfer. (2026, October 2). Troubleshooting failed calls caused by large SIP messages over UDP: source note sip-fragmentation-troubleshooting-sonicwall-internal-only. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-fragmentation-troubleshooting-sonicwall-internal-only

BibTeX

@misc{warmtransfer-claim-sip-fragmentation-troubleshooting-sonicwall-internal-only,
  title  = {Troubleshooting failed calls caused by large SIP messages over UDP: source note sip-fragmentation-troubleshooting-sonicwall-internal-only},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-fragmentation-troubleshooting-sonicwall-internal-only},
  note   = {Source note sip-fragmentation-troubleshooting-sonicwall-internal-only, checked 2026-10-02}
}

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