Source note · SIP OPTIONS pings and trunk keepalives
If the SBC gets 200 OK from the SIP proxy but never receives the proxy's OPTIONS, Microsoft says to check that the Record-Route or Contact FQDN is correct and resolves to the right IP, and that firewall rules allow inbound traffic from all SIP proxy signalling addresses.
Checked 2026-09-24
- Vendor
- Microsoft
- Product
- Teams Phone Direct Routing
- Subsystem
- troubleshooting
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-09-24
- Checked
- 2026-09-24
Sources
- SBC connectivity issues — Microsoft · tier 2 current vendor documentation · section 'SIP options issues' > 'SBC receives "200 OK" response but not SIP options'
Cite this note
APA
WarmTransfer. (2026, September 24). SIP OPTIONS pings and trunk keepalives: source note sip-options-keepalive-dr-200-but-no-options. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-options-keepalive-dr-200-but-no-options
BibTeX
@misc{warmtransfer-claim-sip-options-keepalive-dr-200-but-no-options,
title = {SIP OPTIONS pings and trunk keepalives: source note sip-options-keepalive-dr-200-but-no-options},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-options-keepalive-dr-200-but-no-options},
note = {Source note sip-options-keepalive-dr-200-but-no-options, checked 2026-09-24}
}