eWON General Reference Guide - eWON wiki

3.3.4.3.6 Proxy
3.3.4.3.6.1 Why a proxy feature?
General Reference Guide eWON Configuration
Since firmware 5.2, the eWON has a built-in ProxyServer.
The Proxy feature is similar to the transparent forwarding, with some advantages and some drawbacks.
To be precise, it is not exactly equivalent to the transparent forwarding that forwards all the ports (except the 81), but more like a "port forwarding"
feature that would forward some ports.
The main advantage of the proxy implementation is that the "proxy's destination device" must NOT define the eWON as its gateway.
3.3.4.3.6.2 Comments on the proxy feature
• Overhead
There is an important difference between a forwarded packet and a proxied packet . When the packet is forwarded, it is modified at a very low
level of the stack, then it is immediately resent without any further interpretation, manipulation or storage.
When the packet is proxied, the stack must first maintain storage for the proxied sockets, then every packet must walk the stack all way up to
the proxy application, then all the way down to be resent.
This means an additional load for the system.
• Proxied ports must be known and configured
In "Forwarding" mode all ports are forwarded, there is no need to configure anything.
In Proxied mode, the user must know what port(s) he wants to forward and what protocol (UDP,TCP, FTP) will flow on the port.
• More intrusive content
As said before in "Forwarding" mode, the packet is resent "as received". If it contains 4 bytes, 4 bytes are resent. This is not true in the proxy
mode as the received data are (at least may be) re-aggregated at the proxy level.
Example: if the client sends a 4 bytes packet followed by a 2 bytes packet, then the proxy can resend a 6 bytes packet to the "proxy's
destination device". From a TCP point of view, there is no difference, but from a behavior point of view, there is a slight difference.
One must check what protocol are considered here with the "proxy's destination device" and check if there is a chance that the proxy may
disturb the client-"proxy's destination device" discussion.
3.3.4.3.6.3 Configuration.
Figure 52: Proxy configuration page
RG-001-0-EN ver 1.14 eWON® - 02/05/2012 - ©eWON sa Page 62