Configuring the Firewall

Your Aspera transfer product requires access through the ports listed below. If you cannot establish the connection, review your local corporate firewall settings and remove the port restrictions accordingly.

Point-to-Point Client

Configure your firewall to allow the following ports:

  • Inbound TCP/22 (or other TCP port set for SSH connections): The port for SSH connections.
    Important: Aspera strongly recommends running the SSH server on a non-default port (allowing inbound SSH connections on TCP/33001, and disallowing inbound connections on TCP/22) to ensure that your server remains secure from SSH port scan attacks. For instructions on how to change your SSH port, see Securing Your SSH Server.

    If you have a legacy customer base utilizing TCP/22, then you can allow inbound connections on both ports. Please refer to the topic Securing Your SSH Server for details.

    The firewall on the server side must allow the open TCP port to reach the Aspera server. No servers are listening on UDP ports. When a transfer is initiated by an Aspera client, the client opens an SSH session to the SSH server on the designated TCP port and negotiates the UDP port over which the data transfer will occur.

  • Inbound UDP/33001 (or a range, if required, see below): The port for FASP transfers, which use UDP/33001 by default, although the server may also choose to run FASP transfers on another port.
  • Local firewall: If you have a local firewall on your server (like iptables), verify that it is not blocking your SSH and FASP transfer ports (such as TCP/UDP 33001). If you are using Vlinks, you will need to allow the Vlink UDP port (55001, by default) for multicast traffic. For additional information on setting up Vlinks, see Setting Up Virtual Links (Command Line).

Remote Client Machines

Typically, consumer and business firewalls allow direct outbound connections from client computers on TCP and UDP, and no configuration is required for Aspera transfers. In the special case of firewalls blocking direct outbound connections, usually with proxy servers for web browsing, the following ports must be allowed:
  • Outbound TCP/33001: Allow outbound connections from the Aspera client on the TCP port (TCP/33001 by default, when connecting to a Windows server, or on another non-default port for other server operating systems).
  • Outbound UDP/33001 (or a range, if required): Allow outbound connections from the Aspera client on the FASP UDP port (33001, by default).
  • Local firewall: If you have a local firewall on the client (such as iptables), verify that it is not blocking your SSH and FASP transfer ports (such as TCP/UDP 33001).
Important: Multiple concurrent clients cannot connect to a Windows Aspera server on the same UDP port. Similarly, multiple concurrent clients that are utilizing two or more user accounts cannot connect to a Mac OS X, FreeBSD, or Isilon Aspera server on the same UDP port. If connecting to these servers, you will need to allow a range of outbound connections from the Aspera client (that have been opened incrementally on the server side, starting at UDP/33001). For example, you may need to allow outbound connections on UDP/33001 through UDP/33010 if 10 concurrent connections are allowed by the server.