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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

Provider IPs for IP-authenticated trunks​

For every IP-authenticated trunk, add the provider's incoming SIP addresses to the gateway's Provider IPs tab. FS PBX uses these entries to populate the providers access control list (ACL), which allows inbound calls from that provider.

  1. Open the gateway and select Provider IPs.
  2. Click Add Item and enter an address or CIDR range in IP / CIDR.
  3. Add a separate row for every incoming SIP address or range supplied by the provider, including any failover sources.
  4. Click Save. FS PBX updates the providers ACL and reloads it on the server you are using.

Proxy specifies where FS PBX sends calls. Provider IPs specifies where the provider sends calls from, so entering a proxy alone does not complete inbound setup. Use the provider's published incoming SIP addresses here; your PBX's public IP belongs in the provider's account configuration.

On redundant installations, apply and verify the provider ACL on every server that may receive incoming calls.

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
  • For IP-authenticated trunks, fill in Provider IPs so the providers ACL allows inbound calls
  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.)