# Why NAT Type Matters for Support

Source: https://urbanx.co.za/knowledge-hub/support-diagnostics/nat-type-matters-support

**Answer:** NAT type determines how your connection handles inbound traffic and peer-to-peer sessions. Strict or double NAT can block multiplayer connectivity. Support teams check NAT status to identify CGNAT, port mapping issues, or router configuration problems before escalation.

Part of [Gamer-Centric Support & Intelligent Diagnostics](https://urbanx.co.za/knowledge-hub/support-diagnostics) · 9 min read · by UrbanX Support Engineering

## What NAT Type Means

NAT (Network Address Translation) controls how devices inside your home network communicate with the public internet. Gaming platforms classify NAT into three types:

- Open NAT — Inbound and outbound connections allowed
- Moderate NAT — Some inbound restrictions
- Strict NAT — Most inbound connections blocked

NAT type affects:

- Peer-to-peer connectivity
- Voice chat
- Party matchmaking
- Hosting ability

> **INFO:** NAT type does not directly change latency, but it affects connection reliability.

## Why Support Asks About NAT Type

When diagnosing multiplayer issues, support needs to determine whether:

- The problem is routing-based
- The issue is peer-to-peer connectivity
- Inbound ports are blocked
- CGNAT is restricting traffic
- Double NAT is present

NAT status helps classify the fault before it enters the ticket lifecycle. See lifecycle context: [What Happens After You Log a Fibre Ticket?](/knowledge-hub/support-diagnostics/after-logging-fibre-ticket)

## NAT Type Comparison

| NAT Type | Inbound Traffic | Peer-to-Peer Connectivity | Likely Cause |
| --- | --- | --- | --- |
| Open | Allowed | Full connectivity | Public IP / correct port mapping |
| Moderate | Partially restricted | Limited matchmaking | Router firewall rules |
| Strict | Blocked | Frequent connection failures | Double NAT / CGNAT / firewall |

Strict NAT often causes: unable to join parties, matchmaking errors, and voice chat failure. It does not usually indicate a fibre line fault.

## Common Causes of Strict NAT

There are three primary causes of Strict NAT on residential fibre:

1. **Double NAT**
   - Occurs when both the ISP router and the customer router perform NAT.
   - Inbound traffic must pass through two translation layers, which often results in Strict NAT.
2. **CGNAT (Carrier-Grade NAT)**
   - Due to IPv4 scarcity, many residential fibre services use CGNAT.
   - Under CGNAT: multiple customers share one public IPv4 address, inbound port mapping is restricted, and hosting or peer-to-peer connections may fail.
   - CGNAT does not indicate a fault. It is an address allocation model.
3. **Disabled UPnP or Manual Port Blocking**
   - UPnP (Universal Plug and Play) allows devices to request port mappings automatically.
   - If UPnP is disabled or firewall rules are restrictive, NAT type may degrade to Moderate or Strict.

## Diagnostic Decision Flow

1. **Identify NAT Type on Console or PC**
   - Check network settings: Open / Moderate / Strict.
   - If Open — NAT is not the issue. If Moderate or Strict — continue.
2. **Confirm Double NAT**
   - Is there more than one router in the network?
   - Is the ISP device in router mode instead of bridge mode?
   - Double NAT must be resolved before escalation.
3. **Determine CGNAT Status**
   - If the public IP differs from the WAN IP shown in the router, or inbound connections are consistently blocked, CGNAT may be active.
   - This may require ISP-side IP allocation change, not FNO escalation.
4. **Eliminate Local Firewall Restrictions**
   - Verify UPnP is enabled, no restrictive firewall policies are active, and no manual incorrect port forwarding exists.
   - If NAT remains Strict after validation, support can investigate IP assignment.

## Key Term: CGNAT

- **CGNAT (Carrier-Grade NAT)** — A system where multiple customers share a single public IPv4 address. It conserves address space but restricts inbound connections, which can impact multiplayer gaming and NAT classification.

## Why NAT Type Is a Support Variable

NAT type helps support determine:

- Whether the issue is connectivity vs physical line fault
- Whether escalation to FNO is irrelevant
- Whether IP configuration adjustment is required
- Whether router configuration needs correction

> **WARNING:** Strict NAT does not justify FNO escalation. It is not an access-layer failure.

## South African Context

In South Africa:

- IPv4 scarcity drives CGNAT adoption
- Residential fibre often defaults to shared IP pools
- Public IP allocation may be optional

Support must distinguish between physical fibre outage, ISP authentication issue, and NAT configuration limitation. NAT classification prevents unnecessary escalation in the open-access model.

## When NAT Requires ISP Intervention

ISP-side changes may be required if:

- CGNAT prevents required inbound traffic
- Static public IP is requested
- Authentication profile is misassigned

> **INFO:** These are ISP-layer adjustments, not FNO faults.

## Common Misconceptions

Clarifying what NAT type does and does not indicate:

- Strict NAT does not mean your fibre is broken
- Strict NAT does not increase latency
- NAT type does not indicate packet loss
- Escalation to FNO will not fix NAT classification

NAT is a routing and address translation configuration issue.

## Frequently Asked Questions

**Does Strict NAT cause high ping?**

No. It affects connectivity type, not latency directly.

**Can CGNAT be removed?**

In some cases, a public IP can be provisioned by the ISP.

**Is port forwarding required for Open NAT?**

Often yes, unless UPnP handles mapping automatically.

**Will rebooting fix NAT type?**

Only if the issue is temporary IP assignment. Persistent Strict NAT requires configuration change.

**Should NAT issues be escalated to an FNO?**

No. NAT classification is an ISP or router configuration matter.