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Gateways

In FS PBX, a Gateway is how your PBX connects to the outside world—usually to a SIP carrier (VoIP provider) so you can make and receive calls using real phone numbers (DIDs).

If you’re coming from Asterisk: Gateway ≈ SIP Trunk registration/peer.

What a Gateway is (plain English)​

A Gateway is the PBX’s connection details for a carrier, such as:

  • Carrier host / IP / domain
  • Username + password (if the trunk registers)
  • Transport (UDP/TCP/TLS)
  • Codec preferences (optional)
  • NAT / keepalive behavior (depending on network)

A Gateway is typically used for:

  • Outbound calling (PBX → carrier)
  • Inbound calls (carrier → PBX), usually to your DIDs

Gateway vs DID vs Routing​

These often get mixed up:

  • Gateway: the connection to the provider
  • DID: the inbound phone number (like (555) 222-0000)
  • Destination / Call Routing: what happens when a DID is called (extension, ring group, IVR, queue, etc.)

A good mental model:

Carrier ⇄ Gateway ⇄ FS PBX ⇒ (DID match) ⇒ Destination (IVR/Ring Group/Extension)

Two common gateway types​

1) Registration-based trunk (most common)​

FS PBX “registers” to the carrier using a username/password.

  • Pros: simple, common with ITSPs
  • Cons: NAT/keepalive details matter more

2) IP-auth trunk (no registration)​

Carrier sends calls to your public IP and expects outbound calls from your IP.

  • Pros: often more stable, fewer registration issues
  • Cons: requires static IP and provider-side configuration

Do I need a Gateway for internal calling?​

No. Extensions can call each other with no gateways at all.

You only need a Gateway when you want:

  • outbound calling to PSTN (regular phone numbers)
  • inbound DIDs from a provider

Multi-tenant notes (Domains)​

In a multi-tenant FS PBX system, you can design gateways in a few ways:

Per-domain gateways (most common for hosting)​

Each Domain/customer has their own carrier trunk(s).

  • Cleaner separation
  • Easier per-customer billing and caller ID control

Shared gateways (common for internal enterprise)​

Multiple Domains share one or more carrier connections.

  • Simpler carrier management
  • Requires more careful caller ID, DID mapping, and routing so calls land in the correct Domain

Typical setup workflow​

  1. Create the Gateway
  • Provider host
  • Auth info (if registration trunk)
  • Transport / port as required
  • Apply any provider-specific requirements
  1. Confirm the gateway is healthy
  • If it registers: confirm it shows as registered (wherever your system displays it)
  • If it’s IP-auth: confirm inbound calls reach your PBX and outbound is allowed
  1. Create Outbound Routes
  • Define dialing patterns (911, local, long distance, international, etc.)
  • Select which gateway(s) the route uses
  • Set caller ID rules if needed
  1. Add inbound DID routing

  • Map each DID to a destination inside the correct Domain:

    • extension
    • ring group
    • IVR
    • queue
    • call flow
  1. Test
  • Outbound: local + long distance (and 911/emergency per your policy)
  • Inbound: each DID → correct destination
  • Caller ID: shows correctly for each tenant/site

Common questions & gotchas​

“I created a gateway—why can’t I make calls?”​

Usually one of:

  • No outbound route exists, or the dial pattern doesn’t match what you dialed
  • Provider requires a specific dial format (E.164 like +15551234567)
  • NAT/firewall/SIP ALG issues
  • Wrong codecs or transport

“Inbound calls hit the PBX but don’t reach the right tenant”​

Usually:

  • DID isn’t mapped correctly, or
  • routing is pointing to the wrong Domain/destination

“Do I need multiple gateways?”​

Only if you want:

  • separate carriers (failover / cost routing)
  • multiple sites/tenants with separate trunks
  • a dedicated gateway for specific call types (fax, international, etc.)