Configuring HTTP and HTTPS Fallback

HTTP fallback serves as a secondary transfer method when the Internet connectivity required for Aspera accelerated transfers (UDP port 33001, by default) is unavailable. When HTTP fallback is enabled and UDP connectivity is lost or cannot be established, the transfer will continue over the HTTP protocol. The instructions below walk through the process of setting up HTTP/HTTPS fallback. For additional information on configuring different modes and testing, see the Aspera KB Article "HTTP fallback configuration, testing and troubleshooting."

To enable HTTP Fallback for IBM Aspera Faspex, you must configure the feature in both Faspex and the associated transfer node. The transfer node must be running an Aspera transfer server product (IBM Aspera Enterprise Server or IBM Aspera Connect Server) enabled with a Connect Server license. If Faspex and the transfer server are installed on the same machine, the Faspex installation process configures them automatically. In the case of a remote server, you must configure the transfer server and firewall ports in either of the following ways:

Set HTTP/HTTPS to defaults ports (8080 + 8443) and open firewall ports on 8080/8443.
Set HTTP/HTTPS to standard ports (80 + 443) and open firewall ports on 80/443.

Additionally, the transfer server fallback settings must match the Faspex fallback settings. If the settings don't match, Faspex returns a "Package creation failed" error. Ensure that transfer server has HTTP/HTTPS fallback enabled.

Note: Ensure that your HTTP daemon (Aspera HTTPD) is running with sufficient privileges, so that it can modify file ownership.

Go to Server > Configuration > Transfer Options and select Enable HTTP Fallback.
Go to Server > Configuration > Security and select Encrypt Transfers.

Note: If HTTPS fallback is enabled on the transfer server, encrypted transfers must be enabled in Faspex.
Confirm your HTTP fallback port number.
To confirm your HTTP Fallback port number, run the following asctl command:
```
$ asctl faspex:http_fallback_port
```
If you need to modify the Faspex HTTP port, add the port_number to the command:
```
$ asctl faspex:http_fallback_port port_number
```
Important: Do not use this command if Faspex and your transfer server are on the same machine. If you modify the HTTP fallback port, HTTP fallback fails because Apache is hard-coded to route traffic to asperahttpd on port 8080.
(In the transfer server) Configure HTTP/HTTPS fallback settings.
You can configure HTTP/HTTPS Fallback from either the transfer server GUI or aspera.conf.

From the GUI

To edit your settings from the GUI, launch the transfer server and go to Configuration > Global (tab in left pane) > HTTP Fallback (tab in right pane).

Review the following settings:
- Set Enable HTTP to true.
- If you want to allow fallback over HTTPS, set Enable HTTPS to true.
From aspera.conf

To change your HTTP fallback settings from aspera.conf, go to the following directory:
```
/opt/aspera/etc/aspera.conf
```
Confirm the HTTP fallback settings in aspera.conf as shown in the example below. enable_http should be set to true, while the value shown for http_port should match what was displayed when you ran the command asctl faspex:http_fallback_port (default: 8080).
```
<CONF version="2">
  ...
  <http_server>
    ...
    <enable_http>true</enable_http>     
    ...
    <http_port>8080</http_port>         
    ...
  </http_server>
</CONF>
```
After modifying aspera.conf, restart the Aspera Central, Aspera NodeD, and Aspera HTTPD services:
```
# service asperacentral restart
# service asperanoded restart
# /etc/init.d/asperahttpd restart
```
Run the following command (from Enterprise Server's bin directory) to validate your updated configuration file:
```
$ /opt/aspera/bin/asuserdata -v
```