{
  "id": "communication/sip-403-forbidden-registration",
  "signature": "SIP/2.0 403 Forbidden on REGISTER request",
  "signature_zh": "SIP/2.0 403 禁止注册请求",
  "regex": "SIP/2\\.0 403 Forbidden",
  "domain": "communication",
  "category": "auth_error",
  "subcategory": null,
  "root_cause": "SIP server rejects registration due to mismatched credentials, stale nonce, or IP-based access control.",
  "root_cause_type": "generic",
  "root_cause_zh": "SIP服务器因凭据不匹配、nonce过时或基于IP的访问控制而拒绝注册。",
  "versions": [
    {
      "version": "RFC 3261",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "Kamailio 5.6",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "Asterisk 20",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "FreeSWITCH 1.10",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "Re-enter the same SIP username and password in the client settings",
      "why_fails": "Credentials may be correct but the nonce (challenge) is stale or the server requires digest authentication re-challenge",
      "fail_rate": 0.6,
      "condition": "",
      "sources": []
    },
    {
      "action": "Disable SIP ALG in the router to bypass firewall issues",
      "why_fails": "403 is not a network traversal error; it's an authentication/authorization failure at the application layer",
      "fail_rate": 0.8,
      "condition": "",
      "sources": []
    },
    {
      "action": "Change the SIP transport from UDP to TCP",
      "why_fails": "Transport protocol does not affect authentication validity; the 403 is generated after the transport handshake succeeds",
      "fail_rate": 0.9,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Regenerate the SIP digest credentials: delete the stored nonce and password hash on the client, then force a fresh REGISTER with the correct username and password. On Linphone, remove the account and re-add it. On a custom client, clear the cached credentials and call sip_register() again.",
      "success_rate": 0.7,
      "how": "Regenerate the SIP digest credentials: delete the stored nonce and password hash on the client, then force a fresh REGISTER with the correct username and password. On Linphone, remove the account and re-add it. On a custom client, clear the cached credentials and call sip_register() again.",
      "condition": "",
      "sources": []
    },
    {
      "action": "Verify the SIP server's IP access control list (ACL). On Kamailio, check 'allow_trusted' and 'allow_source_address' settings. Add the client's public IP to the trusted list if needed.",
      "success_rate": 0.8,
      "how": "Verify the SIP server's IP access control list (ACL). On Kamailio, check 'allow_trusted' and 'allow_source_address' settings. Add the client's public IP to the trusted list if needed.",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "Regenerate the SIP digest credentials: delete the stored nonce and password hash on the client, then force a fresh REGISTER with the correct username and password. On Linphone, remove the account and re-add it. On a custom client, clear the cached credentials and call sip_register() again.",
    "Verify the SIP server's IP access control list (ACL). On Kamailio, check 'allow_trusted' and 'allow_source_address' settings. Add the client's public IP to the trusted list if needed."
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://datatracker.ietf.org/doc/html/rfc3261#section-21.4.4",
  "official_doc_section": null,
  "error_code": "403",
  "verification_tier": "ai_generated",
  "confidence": 0.85,
  "fix_success_rate": 0.75,
  "resolvable": "partial",
  "first_seen": "2024-03-15",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}