Skip to Content

Changes for page SIP

Last modified by Aaron Blackburn on 2026/09/01 19:00
From version 1.1
edited by Aaron Blackburn
on 2026/07/22 20:53
Change comment: There is no comment for this version
To version 1.4
edited by Aaron Blackburn
on 2026/09/01 19:00
Change comment: There is no comment for this version

Summary

Details

Page properties
Content
... ... @@ -1,0 +1,438 @@
1 +{{html clean="false"}}
2 +<!--
3 + XWiki usage: Paste into an HTML macro on your page.
4 + Note: All FirstDigital public IPs have been sanitized for public wiki security.
5 +-->
6 +<style>
7 + @import url('https://fonts.googleapis.com/css2?family=Host+Grotesk:wght@300;400;500;600;700;800&display=swap');
8 +
9 + .fd-sip-doc, .fd-sip-doc * { box-sizing: border-box; }
10 + .fd-sip-doc {
11 + --fd-navy: #003366;
12 + --fd-dark-navy: #001a33;
13 + --fd-blue: #307ab2;
14 + --fd-sky: #38b2e3;
15 + --fd-bright-cyan: #5ed2ff;
16 + --fd-red: #cf333d;
17 + --fd-green: #2e7d32;
18 + --fd-slate: #2e404d;
19 + --fd-grey: #8f9499;
20 + --fd-lightgrey: #e2e8f0;
21 + --fd-offwhite: #f8fafc;
22 + --fd-max-w: 1140px;
23 +
24 + font-family: 'Host Grotesk', system-ui, -apple-system, sans-serif;
25 + color: var(--fd-slate);
26 + background: #ffffff;
27 + max-width: var(--fd-max-w);
28 + margin: 0 auto;
29 + padding: 24px 16px;
30 + }
31 +
32 + /* Header */
33 + .fd-sip-doc .doc-header {
34 + background: radial-gradient(circle at 50% 35%, rgba(13, 71, 128, 0.78) 0%, rgba(0, 51, 102, 0.93) 60%, rgba(0, 26, 51, 0.98) 100%),
35 + url('Fiber Optic Theme.JPG') center/cover no-repeat;
36 + padding: 40px 32px;
37 + border-radius: 20px;
38 + text-align: center;
39 + color: #ffffff;
40 + box-shadow: inset 0 0 60px rgba(0, 26, 51, 0.6), 0 12px 32px rgba(0, 51, 102, 0.12);
41 + margin-bottom: 32px;
42 + }
43 + .fd-sip-doc .doc-header p.kicker {
44 + color: var(--fd-bright-cyan);
45 + font-weight: 800;
46 + font-size: .8rem;
47 + text-transform: uppercase;
48 + letter-spacing: .18em;
49 + margin: 0 0 8px;
50 + text-shadow: 0 2px 10px rgba(0, 26, 51, 0.8);
51 + }
52 + .fd-sip-doc .doc-header h1 {
53 + font-weight: 800;
54 + font-size: 2.25rem;
55 + margin: 0 0 10px;
56 + letter-spacing: -0.02em;
57 + text-shadow: 0 3px 12px rgba(0, 26, 51, 0.9);
58 + }
59 + .fd-sip-doc .doc-header p.sub {
60 + color: #f8fafc;
61 + font-weight: 400;
62 + font-size: 1rem;
63 + max-width: 680px;
64 + margin: 0 auto;
65 + line-height: 1.5;
66 + text-shadow: 0 2px 8px rgba(0, 26, 51, 0.95);
67 + }
68 +
69 + /* Disclaimer Banner */
70 + .fd-sip-doc .disclaimer-box {
71 + background: #f0f7fc;
72 + border-left: 5px solid var(--fd-blue);
73 + padding: 16px 20px;
74 + border-radius: 8px;
75 + margin-bottom: 28px;
76 + font-size: 0.9rem;
77 + line-height: 1.5;
78 + }
79 +
80 + /* Section Titles */
81 + .fd-sip-doc .section-title {
82 + color: var(--fd-navy);
83 + font-size: 1.35rem;
84 + font-weight: 700;
85 + margin: 36px 0 16px;
86 + border-bottom: 2px solid var(--fd-lightgrey);
87 + padding-bottom: 8px;
88 + }
89 +
90 + /* Embedded Diagram Containers */
91 + .fd-sip-doc .diagram-card {
92 + background: #ffffff;
93 + border: 1px solid var(--fd-lightgrey);
94 + border-radius: 16px;
95 + padding: 24px;
96 + margin-bottom: 28px;
97 + box-shadow: 0 6px 20px rgba(0, 30, 60, 0.05);
98 + text-align: center;
99 + }
100 + .fd-sip-doc .diagram-card svg {
101 + max-width: 100%;
102 + height: auto;
103 + }
104 + .fd-sip-doc .diagram-caption {
105 + font-size: 0.85rem;
106 + color: var(--fd-slate);
107 + margin-top: 12px;
108 + font-weight: 500;
109 + }
110 +
111 + /* Specifications Grid */
112 + .fd-sip-doc .specs-grid {
113 + display: grid;
114 + grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
115 + gap: 16px;
116 + margin-bottom: 32px;
117 + }
118 + .fd-sip-doc .spec-card {
119 + background: var(--fd-offwhite);
120 + border: 1px solid var(--fd-lightgrey);
121 + border-radius: 12px;
122 + padding: 16px 20px;
123 + }
124 + .fd-sip-doc .spec-card .label {
125 + font-size: 0.75rem;
126 + text-transform: uppercase;
127 + font-weight: 700;
128 + color: var(--fd-grey);
129 + letter-spacing: 0.05em;
130 + margin-bottom: 4px;
131 + }
132 + .fd-sip-doc .spec-card .val {
133 + font-size: 1rem;
134 + font-weight: 700;
135 + color: var(--fd-navy);
136 + }
137 + .fd-sip-doc .spec-card .subtext {
138 + font-size: 0.8rem;
139 + color: var(--fd-slate);
140 + margin-top: 4px;
141 + }
142 +
143 + /* Rules Grid */
144 + .fd-sip-doc .rules-grid {
145 + display: grid;
146 + grid-template-columns: 1fr 1fr;
147 + gap: 20px;
148 + margin-bottom: 32px;
149 + }
150 + .fd-sip-doc .rule-box {
151 + border: 1px solid var(--fd-lightgrey);
152 + border-radius: 12px;
153 + padding: 20px;
154 + background: #ffffff;
155 + box-shadow: 0 4px 12px rgba(0, 0, 0, 0.03);
156 + }
157 + .fd-sip-doc .rule-box h4 {
158 + margin: 0 0 12px;
159 + color: var(--fd-navy);
160 + font-size: 1.05rem;
161 + }
162 + .fd-sip-doc .rule-box ul {
163 + margin: 0;
164 + padding-left: 20px;
165 + font-size: 0.88rem;
166 + line-height: 1.6;
167 + }
168 +
169 + /* Troubleshooting Table */
170 + .fd-sip-doc .tb-table {
171 + width: 100%;
172 + border-collapse: collapse;
173 + margin-bottom: 32px;
174 + font-size: 0.9rem;
175 + }
176 + .fd-sip-doc .tb-table th {
177 + background: var(--fd-navy);
178 + color: #ffffff;
179 + text-align: left;
180 + padding: 12px 16px;
181 + font-weight: 700;
182 + }
183 + .fd-sip-doc .tb-table th:first-child { border-top-left-radius: 8px; }
184 + .fd-sip-doc .tb-table th:last-child { border-top-right-radius: 8px; }
185 + .fd-sip-doc .tb-table td {
186 + padding: 14px 16px;
187 + border-bottom: 1px solid var(--fd-lightgrey);
188 + line-height: 1.5;
189 + }
190 + .fd-sip-doc .tb-table tr:nth-child(even) { background: var(--fd-offwhite); }
191 + .fd-sip-doc .symptom { font-weight: 700; color: var(--fd-red); width: 28%; }
192 +
193 + @media (max-width: 768px) {
194 + .fd-sip-doc .rules-grid { grid-template-columns: 1fr; }
195 + }
196 +</style>
197 +
198 +<div class="fd-sip-doc">
199 +
200 + <!-- Header Banner -->
201 + <div class="doc-header">
202 + <p class="kicker">FirstDigital Voice Operations</p>
203 + <h1>SIP Trunking Technical Reference</h1>
204 + <p class="sub">Network architecture, firewall requirements, and troubleshooting standards for customer SIP trunks.</p>
205 + </div>
206 +
207 + <!-- Disclaimer Notice -->
208 + <div class="disclaimer-box">
209 + <strong>Customer Responsibility Notice:</strong> Customers are responsible for the configuration and maintenance of their own routers, firewalls, and PBX equipment. FirstDigital provides these specifications to assist engineers during trunk integration.
210 + </div>
211 +
212 + <!-- DIAGRAM 1: Network Topology -->
213 + <div class="section-title">1. SIP Trunk Topology & Traffic Routing</div>
214 + <div class="diagram-card">
215 + <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 800 300" style="font-family:'Host Grotesk', system-ui, sans-serif;">
216 + <!-- Cloud Node -->
217 + <rect x="30" y="50" width="200" height="200" rx="12" fill="#f0f7fc" stroke="#307ab2" stroke-width="2"/>
218 + <rect x="45" y="35" width="170" height="26" rx="13" fill="#003366"/>
219 + <text x="130" y="52" fill="#ffffff" font-size="11" font-weight="bold" text-anchor="middle">FIRSTDIGITAL CLOUD</text>
220 + <text x="130" y="115" fill="#003366" font-size="14" font-weight="bold" text-anchor="middle">FirstDigital SBC</text>
221 + <rect x="55" y="130" width="150" height="24" rx="4" fill="#e2e8f0"/>
222 + <text x="130" y="146" fill="#2e404d" font-size="11" font-family="monospace" text-anchor="middle">[FirstDigital_SBC_IP]</text>
223 + <text x="130" y="180" fill="#2e404d" font-size="10" text-anchor="middle">Signaling &amp; Audio Target</text>
224 +
225 + <!-- Flow Connectors -->
226 + <path d="M 230 110 L 370 110" stroke="#307ab2" stroke-width="3" stroke-dasharray="6,4"/>
227 + <path d="M 370 160 L 230 160" stroke="#38b2e3" stroke-width="3"/>
228 + <polygon points="230,160 238,155 238,165" fill="#38b2e3"/>
229 + <polygon points="370,110 362,105 362,115" fill="#307ab2"/>
230 + <text x="300" y="100" fill="#003366" font-size="10" font-weight="bold" text-anchor="middle">UDP 5060 (SIP)</text>
231 + <text x="300" y="180" fill="#003366" font-size="10" font-weight="bold" text-anchor="middle">UDP 5k-65k (RTP)</text>
232 +
233 + <!-- Firewall Node -->
234 + <rect x="370" y="50" width="180" height="200" rx="12" fill="#fff5f5" stroke="#cf333d" stroke-width="2"/>
235 + <rect x="385" y="35" width="150" height="26" rx="13" fill="#cf333d"/>
236 + <text x="460" y="52" fill="#ffffff" font-size="11" font-weight="bold" text-anchor="middle">CUSTOMER FIREWALL</text>
237 + <text x="460" y="105" fill="#003366" font-size="13" font-weight="bold" text-anchor="middle">Public Edge Router</text>
238 + <rect x="385" y="120" width="150" height="24" rx="4" fill="#e2e8f0"/>
239 + <text x="460" y="136" fill="#2e404d" font-size="11" font-family="monospace" text-anchor="middle">[Customer_Public_IP]</text>
240 + <text x="460" y="175" fill="#cf333d" font-size="10" font-weight="bold" text-anchor="middle">SIP ALG: DISABLED</text>
241 + <text x="460" y="195" fill="#2e404d" font-size="10" text-anchor="middle">Source NAT Active</text>
242 +
243 + <!-- Internal LAN Path -->
244 + <path d="M 550 135 L 610 135" stroke="#2e404d" stroke-width="2"/>
245 +
246 + <!-- PBX Node -->
247 + <rect x="610" y="50" width="160" height="200" rx="12" fill="#f8fafc" stroke="#003366" stroke-width="2"/>
248 + <rect x="625" y="35" width="130" height="26" rx="13" fill="#003366"/>
249 + <text x="690" y="52" fill="#ffffff" font-size="11" font-weight="bold" text-anchor="middle">CUSTOMER PBX</text>
250 + <text x="690" y="115" fill="#003366" font-size="13" font-weight="bold" text-anchor="middle">Internal PBX / SBC</text>
251 + <rect x="625" y="130" width="130" height="24" rx="4" fill="#e2e8f0"/>
252 + <text x="690" y="146" fill="#2e404d" font-size="11" font-family="monospace" text-anchor="middle">192.168.x.x (LAN)</text>
253 + </svg>
254 + <div class="diagram-caption">Figure 1: Standard end-to-end SIP signaling and RTP media pathing via customer firewall.</div>
255 + </div>
256 +
257 + <!-- Specifications Grid -->
258 + <div class="section-title">2. Core Trunk Parameters</div>
259 + <div class="specs-grid">
260 + <div class="spec-card">
261 + <div class="label">Signaling Protocol</div>
262 + <div class="val">UDP 5060</div>
263 + <div class="subtext">Standard SIP port</div>
264 + </div>
265 + <div class="spec-card">
266 + <div class="label">Primary Codec</div>
267 + <div class="val">G.711u</div>
268 + <div class="subtext">20ms packetization</div>
269 + </div>
270 + <div class="spec-card">
271 + <div class="label">DTMF Mode</div>
272 + <div class="val">RFC 2833</div>
273 + <div class="subtext">Out-of-band touch tones</div>
274 + </div>
275 + <div class="spec-card">
276 + <div class="label">DNIS Delivery</div>
277 + <div class="val">10 Digits</div>
278 + <div class="subtext">+1 stripped; Intl disabled by default</div>
279 + </div>
280 + <div class="spec-card">
281 + <div class="label">Authentication</div>
282 + <div class="val">IP Registration-less</div>
283 + <div class="subtext">No user/password required</div>
284 + </div>
285 + <div class="spec-card">
286 + <div class="label">SIP Advanced</div>
287 + <div class="val">Peer Path / Re-invite</div>
288 + <div class="subtext">Disabled / No re-invites permitted</div>
289 + </div>
290 + </div>
291 +
292 + <!-- DIAGRAM 2: REWORKED FIREWALL PACKET FILTER & PORT MAP ILLUSTRATION -->
293 + <div class="section-title">3. Firewall Policy Rules & Packet Filter Action</div>
294 + <div class="diagram-card">
295 + <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 800 290" style="font-family:'Host Grotesk', system-ui, sans-serif;">
296 + <!-- Outer Frame -->
297 + <rect x="10" y="10" width="780" height="270" rx="12" fill="#f8fafc" stroke="#e2e8f0" stroke-width="2"/>
298 +
299 + <!-- FirstDigital WAN Side -->
300 + <text x="110" y="40" fill="#003366" font-size="12" font-weight="bold" text-anchor="middle">WAN SOURCE</text>
301 + <text x="110" y="58" fill="#2e404d" font-size="11" font-family="monospace" text-anchor="middle">[FirstDigital_Subnet]</text>
302 +
303 + <!-- Firewall Barrier (Middle) -->
304 + <rect x="360" y="30" width="80" height="230" rx="8" fill="#fff5f5" stroke="#cf333d" stroke-width="2"/>
305 + <text x="400" y="135" fill="#cf333d" font-size="12" font-weight="bold" text-anchor="middle" transform="rotate(-90,400,135)">FIREWALL BOUNDARY</text>
306 +
307 + <!-- Customer LAN Side -->
308 + <text x="690" y="40" fill="#003366" font-size="12" font-weight="bold" text-anchor="middle">LAN DESTINATION</text>
309 + <text x="690" y="58" fill="#2e404d" font-size="11" font-family="monospace" text-anchor="middle">[Customer_PBX_IP]</text>
310 +
311 + <!-- ROW 1: SIP SIGNALING (PASS) -->
312 + <path d="M 200 90 L 360 90" stroke="#2e7d32" stroke-width="2.5"/>
313 + <circle cx="380" cy="90" r="10" fill="#2e7d32"/>
314 + <text x="380" y="94" fill="#ffffff" font-size="11" font-weight="bold" text-anchor="middle">✓</text>
315 + <path d="M 400 90 L 580 90" stroke="#2e7d32" stroke-width="2.5"/>
316 + <polygon points="580,90 572,85 572,95" fill="#2e7d32"/>
317 +
318 + <rect x="220" y="72" width="120" height="22" rx="4" fill="#e8f5e9" stroke="#2e7d32"/>
319 + <text x="280" y="87" fill="#2e7d32" font-size="10" font-weight="bold" text-anchor="middle">SIP: UDP 5060</text>
320 + <text x="480" y="82" fill="#2e7d32" font-size="10" font-weight="bold" text-anchor="middle">FORWARD TO PBX</text>
321 +
322 + <!-- ROW 2: RTP AUDIO STREAM (PASS) -->
323 + <path d="M 200 150 L 360 150" stroke="#307ab2" stroke-width="2.5"/>
324 + <circle cx="380" cy="150" r="10" fill="#2e7d32"/>
325 + <text x="380" y="154" fill="#ffffff" font-size="11" font-weight="bold" text-anchor="middle">✓</text>
326 + <path d="M 400 150 L 580 150" stroke="#307ab2" stroke-width="2.5"/>
327 + <polygon points="580,150 572,145 572,155" fill="#307ab2"/>
328 +
329 + <rect x="210" y="132" width="140" height="22" rx="4" fill="#f0f7fc" stroke="#307ab2"/>
330 + <text x="280" y="147" fill="#003366" font-size="10" font-weight="bold" text-anchor="middle">RTP: UDP 5k - 65k</text>
331 + <text x="480" y="142" fill="#003366" font-size="10" font-weight="bold" text-anchor="middle">ALLOW MEDIA STREAM</text>
332 +
333 + <!-- ROW 3: SIP ALG / INSPECTION (BLOCKED) -->
334 + <path d="M 200 215 L 360 215" stroke="#cf333d" stroke-width="2.5" stroke-dasharray="4,4"/>
335 + <circle cx="380" cy="215" r="10" fill="#cf333d"/>
336 + <text x="380" y="219" fill="#ffffff" font-size="11" font-weight="bold" text-anchor="middle">✕</text>
337 +
338 + <rect x="220" y="197" width="120" height="22" rx="4" fill="#fff5f5" stroke="#cf333d"/>
339 + <text x="280" y="212" fill="#cf333d" font-size="10" font-weight="bold" text-anchor="middle">SIP ALG / STUN</text>
340 + <text x="485" y="212" fill="#cf333d" font-size="11" font-weight="bold">DISABLED (Prevents Header Modification)</text>
341 +
342 + <!-- Bottom Note -->
343 + <rect x="180" y="250" width="440" height="20" rx="4" fill="#e2e8f0"/>
344 + <text x="400" y="264" fill="#2e404d" font-size="10" font-weight="bold" text-anchor="middle">OUTBOUND EGRESS NAT: All traffic MUST egress sourcing from [Customer_Public_IP]</text>
345 + </svg>
346 + <div class="diagram-caption">Figure 2: Firewall packet-filtering policy—explicitly allowing signaling/media while disabling SIP ALG.</div>
347 + </div>
348 +
349 + <!-- Rules Text -->
350 + <div class="rules-grid">
351 + <div class="rule-box">
352 + <h4>Outbound Traffic Requirements</h4>
353 + <ul>
354 + <li>Outbound calls to FirstDigital must source directly from the registered Customer Public IP.</li>
355 + <li>Outbound calls must send Caller ID matching a phone number assigned to the trunk instance.</li>
356 + <li>FirstDigital will automatically reject calls sourcing from unknown or unauthorized IPs.</li>
357 + </ul>
358 + </div>
359 + <div class="rule-box">
360 + <h4>Firewall & NAT Settings</h4>
361 + <ul>
362 + <li><strong>SIP ALG:</strong> Must be completely <u>DISABLED</u> on customer edge firewalls and routers.</li>
363 + <li><strong>RTP Media:</strong> Ensure UDP ports 5000-65000 are permitted for full audio stream delivery.</li>
364 + <li><strong>NAT Routing:</strong> Confirm outbound NAT egress explicitly maps internal PBX traffic to the registered public IP.</li>
365 + </ul>
366 + </div>
367 + </div>
368 +
369 + <!-- DIAGRAM 3: One-Way Audio Problem -->
370 + <div class="section-title">4. Common Audio Defect: Private IP Header Leakage</div>
371 + <div class="diagram-card">
372 + <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 800 240" style="font-family:'Host Grotesk', system-ui, sans-serif;">
373 + <!-- SBC Box -->
374 + <rect x="40" y="40" width="180" height="160" rx="10" fill="#f0f7fc" stroke="#307ab2" stroke-width="2"/>
375 + <text x="130" y="80" fill="#003366" font-size="13" font-weight="bold" text-anchor="middle">FirstDigital SBC</text>
376 + <text x="130" y="100" fill="#2e404d" font-size="10" text-anchor="middle">Public Media Gateway</text>
377 +
378 + <!-- Broken Return Audio Path -->
379 + <path d="M 220 160 L 410 160" stroke="#cf333d" stroke-width="3" stroke-dasharray="4,4"/>
380 + <circle cx="420" cy="160" r="12" fill="#cf333d"/>
381 + <text x="420" y="165" fill="#ffffff" font-size="13" font-weight="bold" text-anchor="middle">X</text>
382 + <text x="315" y="150" fill="#cf333d" font-size="10" font-weight="bold" text-anchor="middle">Audio Fails: 192.168.x.x Unreachable</text>
383 +
384 + <!-- Firewall Box -->
385 + <rect x="450" y="40" width="120" height="160" rx="10" fill="#fff5f5" stroke="#cf333d" stroke-width="2"/>
386 + <text x="510" y="120" fill="#cf333d" font-size="12" font-weight="bold" text-anchor="middle">Firewall</text>
387 +
388 + <!-- PBX Box -->
389 + <rect x="620" y="40" width="140" height="160" rx="10" fill="#f8fafc" stroke="#003366" stroke-width="2"/>
390 + <text x="690" y="75" fill="#003366" font-size="13" font-weight="bold" text-anchor="middle">Customer PBX</text>
391 +
392 + <!-- Problem Header Packet -->
393 + <path d="M 620 85 L 230 85" stroke="#307ab2" stroke-width="2"/>
394 + <rect x="310" y="60" width="240" height="24" rx="4" fill="#fffbe0" stroke="#d97706"/>
395 + <text x="430" y="76" fill="#b45309" font-size="10" font-weight="bold" text-anchor="middle">SDP Header: Audio IP = 192.168.1.50 (Private IP Leak!)</text>
396 + </svg>
397 + <div class="diagram-caption">Figure 3: Why one-way audio occurs—the PBX requests return audio to an unreachable internal private IP address.</div>
398 + </div>
399 +
400 + <!-- Troubleshooting Matrix -->
401 + <div class="section-title">5. Troubleshooting Matrix</div>
402 + <table class="tb-table">
403 + <thead>
404 + <tr>
405 + <th>Symptom</th>
406 + <th>Root Cause & Resolution Step</th>
407 + </tr>
408 + </thead>
409 + <tbody>
410 + <tr>
411 + <td class="symptom">No Inbound Calls</td>
412 + <td>Verify firewall allows <code>UDP 5060</code> from FirstDigital's subnet. Confirm <strong>SIP ALG is disabled</strong> on edge devices.</td>
413 + </tr>
414 + <tr>
415 + <td class="symptom">No Outbound Calls</td>
416 + <td>Confirm outbound SIP traffic is directed to FirstDigital's SBC IP on <code>UDP 5060</code>. Verify traffic sources from your registered Public IP and uses an assigned Caller ID.</td>
417 + </tr>
418 + <tr>
419 + <td class="symptom">One-Way or No Audio</td>
420 + <td><strong>Common Issue:</strong> PBX is leaking private IP addresses (e.g., <code>10.x.x.x</code> or <code>192.168.x.x</code>) in the SIP SDP header. Fix PBX NAT settings, SBC Media Address Override, or STUN configuration. Disable SIP ALG.</td>
421 + </tr>
422 + <tr>
423 + <td class="symptom">Touch Tones Not Working</td>
424 + <td>Configure PBX and endpoints to send DTMF out-of-band using <strong>RFC 2833</strong> (telephony-event).</td>
425 + </tr>
426 + <tr>
427 + <td class="symptom">Calls Routing Incorrectly</td>
428 + <td>Inspect received <strong>DNIS digit delivery</strong>. FirstDigital defaults to 10-digit delivery. Update PBX inbound routing rules to match.</td>
429 + </tr>
430 + <tr>
431 + <td class="symptom">Forwarded Calls Have One-Way Audio</td>
432 + <td>Occurs if FirstDigital enabled "NAT Media" as a temporary workaround for private IP header leaks. Resolving the PBX private IP leak allows FirstDigital to disable NAT Media settings, resolving transfer audio.</td>
433 + </tr>
434 + </tbody>
435 + </table>
436 +
437 +</div>
438 +{{/html}}