Teams Direct Routing - Outbound Issue

Question

We have an on-prem SBC (Ribbon SBC 1000) and configured NAT to have public IP. Everything is checked several times including sbc and firewall configuration(allowing microsoft teams network ranges, ports and protocols). We tested the connectivity between SBC and Microsoft, SBC is sending sip options and microsoft is replying with 200 OK. We can make an inbound test call from SBC to MSFT - call is pushing through while we do not see any call attempt from MSFT side when trying to make an outbound call. Also, the SIP OPTION STATUS of the SBC from TAC is on "Warning".

The FQDN of the SBC is with special character sha-sbc-1000.domain.com. Does it related to the issue? I had found an article with the same issue and fix was to change the dns name different from they are using before with _ or special character.

Reference: https://learn.microsoft.com/en-us/answers/questions/115027/teams-dirfect-routing-sip-options-warning.html

Any ideas to fix the issue?

Answer 1

Hi @Israel Perlawan

Do you mean that Teams user cannot call external user in Teams client?

If none of the users are able to make calls, please make sure that the SIP Signaling IPs and FQDNs are allowed on all network devices that connect the SBC to the internet. The IP addresses that must be allowed are listed at SIP Signaling: FQDNs.

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