Hello all!

We got the following error from the API while connection our
iOS client with an Unwired Server:

411 Content-Length is missing in header.

This error occurs only while connecting to an Unwired
Server, that is within a vpn to our customer. Connecting to
an Unwired Server in our network works. There are no
differences between the server configurations in the Sybase
Control Center.



In the Sybase Infocenter I found the issues CR 693116 and CR
692218:

Devices on 3G/4G network not able to connect to Unwired
Server.
A connectivity issue may occur between the device and
Unwired Server. The current client libraries use a protocol
that supports HTTP chunked transfer-encoding only. 3G/4G
traffic might, in some cases, be subject to content
filtering and convert the messages from chunked
transfer-encoding to fixed content-length if the
communication is done via standard HTTP ports, which most
commonly are 80 and 8080. Since the client application can
support only chunked transfer-encoding, the communication
cannot be established. In effect, a response cannot be sent
back to the server indicating that the device is online.
Note: For devices on WiFi networks, the connection between a
device and Unwired Server establishes without error.
Workaround: Use a non-standard HTTP port (any port other
than 80 or 8080) or an HTTPS port, that is, 443 for Unwired
Platform client communication from devices to the Relay
Server or external load balancer, whichever one is used, in
the DMZ.


Are those issues related to our error? We try connect over
port 5001 and try to synchronize over port 2480. In the
Sybase Control Center we didn't find an standard http port
configurations.

Can you give us any hints? What could be the problem? What
should we check?

regards
Sebastian