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One-way Audio & NAT Troubleshooting
← VoIP & TelephonyAsterisk one-way audio is almost always a NAT problem. I debug and fix it — SIP ALG, RTP ports, externip/localnet configuration, firewall rules.
Typical problems I solve
One-way
Only inbound or outbound audio — the other side hears nothing
NAT
Asterisk behind NAT, RTP packets not reaching the phone
SIP ALG
Router/firewall rewriting SIP headers — audio breaks
Firewall
RTP ports blocked, only SIP signaling gets through
externip
externip/localnet not (properly) configured in sip.conf/pjsip.conf
Specific
This is what I have experience with and can help you with.
- → Diagnose and fix one-way audio (inbound & outbound)
- → NAT traversal configuration (externip, localnet, STUN)
- → SIP ALG detection and disabling on routers/firewalls
- → RTP port range configuration & firewall rules
- → SIP debug analysis (pcap, sngrep, SIP traces)
Other services
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