GoodSync Connect uses the GoodSync Transfer Protocol (GSTP) to connect a GoodSync client to a GoodSync server. The client is the device running the GoodSync Job. The server is the remote device that gives access to the selected files and folders.
GoodSync makes the connection in one of two ways:
- Direct Connection: the devices connect to each other (fastest).
- Forwarded Connection: a GoodSync Forwarder relays the connection when a direct one is not possible.
See Direct vs. Forwarded at a Glance for a quick comparison.
Direct Connection
GoodSync first tries to create a direct peer-to-peer connection between the client and server over TCP/IP. When this succeeds, file data moves directly between the two devices, without passing through an intermediate transfer server.
A direct connection usually gives the best transfer speed and the lowest latency, because the source and destination talk to each other directly.
Examples of direct connections:
- Two computers on the same local network: GoodSync finds the other computer on the network and transfers files directly over TCP port 33333.
- A computer connecting to a remote server: The client contacts the GoodSync Connect service over TCP 80/443 to find the server, and then transfers files directly over TCP port 33333.
Forwarded Connection
In some networks, the client cannot connect directly to the server. Common causes include:
- Network Address Translation (NAT), such as a home or office router.
- Firewall or router restrictions.
- VPN or proxy configurations.
- Endpoint-security software that blocks the connection.
- Restrictions on inbound network connections, such as blocked TCP port 33333.
When a direct connection cannot be made, GoodSync automatically tries to use a GoodSync Forwarder. A Forwarder is a network location that both the client and server can reach. It relays the encrypted GoodSync Connect traffic between them.
A forwarded connection may be slower than a direct one, because the traffic passes through an extra network location.
Example: A laptop at home syncs with a server in an office, but the office firewall blocks incoming connections. GoodSync cannot connect directly, so it routes the connection through a Forwarder and the job runs normally.
NOTE: No user action is normally required. GoodSync automatically checks whether a direct connection is available. It uses a Forwarder only when the devices cannot communicate directly.
IMPORTANT: The Forwarder does not store the files being transferred. It only relays the encrypted connection between the GoodSync client and server. GoodSync Connect is not a cloud-storage service. Transferred files stay in the source and destination locations selected in the GoodSync Job.
Direct vs. Forwarded at a Glance
| Direct Connection | Forwarded Connection | |
|---|---|---|
| Data path | Straight from client to server | Relayed through a GoodSync Forwarder |
| Speed | Usually the fastest, with the lowest latency | May be slower because of the extra hop |
| When it is used | Always tried first | Only when a direct connection fails |
| Encryption | Encrypted | Encrypted. The Forwarder only relays the traffic. |
| Files stored in between | None | None |
Getting a Direct Connection
If your connections are always forwarded and transfers are slow, check that your firewall and endpoint-security software allow GoodSync to use the ports in Ports Used, especially TCP port 33333.