SIP Registration Failed

What Causes This Error

A SIP peer (agent softphone, carrier trunk, or remote extension) is failing to register with the Asterisk server. Common causes: wrong SIP credentials, SIP server address pointing to wrong host, firewall blocking SIP port (5060/5061), NAT traversal issues, codec mismatch, or Asterisk SIP service not running properly.

How to Fix It

• Check registration status: asterisk -rx ‘sip show registry’

• Check peer status: asterisk -rx ‘sip show peers’

• Enable SIP debug to see registration traffic: asterisk -rx ‘sip set debug on’

• 4 Watch for auth failures: tail -f /var/log/asterisk/messages | grep -i ‘auth|register|failed’

• 5 Verify credentials match what’s in sip.conf: cat /etc/asterisk/sip.conf | grep -A10 PEER_NAME

• 6 Check firewall: iptables -L | grep 5060

• 7 Test SIP connectivity from peer: sipsak -s sip:SERVER_IP

• Reload SIP: asterisk -rx ‘sip reload’

How to Prevent It

Implement SIP registration monitoring with alerts on failure. Use fail2ban to protect against SIP brute force (which can consume registration slots). Document carrier SIP credentials in a secure location. Test SIP registration after any network or firewall changes.

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