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My router has a proxy service. Can I test it as a Virtual Service (Port Forwarding)?

Some routers have proxy services enabled which intercept IP packet streams and do a variety of useful tasks, such as modifying IP headers or caching application data for faster subsequent transactions.

The vservice.tcl test module included with CDRouter allows user-defined Virtual Services, also known as Port Mappings, to be tested. A test engineer can configure CDRouter to forward packets through specified TCP or UDP ports on the WAN side of the router. CDRouter will intercept these packets on the LAN side of the router to determine the outcome of the test.

The testvar virtualWANTransType specifies how the source IP address is expected to appear when received and inspected by the CDRouter LAN client. Setting it to none indicates that CDRouter will expect the source IP address to be that of the remote host. Setting it to public indicates that CDRouter will expect the IP source address to be the WAN port address of the router, and setting it to private indicates the IP source address should be the router’s LAN port address.

CDRouter can be configured to test proxy services enabled for a particular protocol or port, such as FTP on port 21, by treating them as Virtual Services. Because the proxy service might rewrite the IP source address of the packet, the results may not be consistent with the value set in virtualWANTransType for other un-proxied Virtual Services. We recommend using a separate configuration specific to testing proxy services for this reason.

Here is an example of a configuration for testing an FTP proxy service using the vservice.tcl test module:

testvar virtualTcpServicePort1 21
testvar virtualTcpServiceHost1
testvar virtualTcpServiceName1 ftp

Additionally, the virtualWANTransType testvar must be set to public:

testvar virtualWANTransType public

Finally, the port for the proxy service must also be listed in the testvar firewallTcpOpenPorts list if the firewall.tcl test module is also going to be run:

testvar firewallTcpOpenPorts "21"