> For the complete documentation index, see [llms.txt](https://trialkey.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trialkey.gitbook.io/docs/arcamatic-backup/troubleshooting/firewalls.md).

# Firewalls

Many computers reside behind a firewall so there is a good chance that at least one of the computers between the **Arcamatic Client** and **Arcamatic Server** will have a firewall active (this will not likely be the case if you are transferring files within a LAN).

If you were able to run the client and server on the same machine but are having connectivity issues once they are on separate machines, check to see if there is a firewall that might be blocking the connection between the client and server.  If so, you may need to open the port on the machine where the **Arcamatic Server** sits so that the **Arcamatic Client** can connect to it.

**Arcamatic** is configured by default to use port 2639 but this can be changed to any port that is required.