Building ATS for transparency

In most cases, if your environment supports transparency then configure will automatically enable it. For other environments you may need to twiddle the configure options.

--enable-posix-cap
This enables POSIX capabilities, which are required for transparency. These are compiled in by default. To check your system, look for the header file sys/capability.h and the system library libcap. These are in the packages libcap and libcap-devel contra-respectively.
--enable-tproxy[=value]
Enable TPROXY support, which is the Linux kernel feature used for transparency. This should be present in the base installation, there is no package associated with it.
auto
Do automatic checks for the the TPROXY header file (linux/in.h) and enable TPROXY support if the IP_TRANSPARENT definition is present. This is the default if this option is not specified or value is omitted.
no
Do not check for TPROXY support, disable support for it.
force
Do not check for TPROXY support, enable it using the $ats@ built in value for IP_TRANSPARENT. This is useful for systems that have it in the kernel for but some reason do not have the appropriate system header file.
number
Do not check for TPROXY support, use number as the IP_TRANSPARENT value. There are, at present, no known standard distributions of Linux that support TPROXY but use a value different from the built in ATS default. However, a custom built kernel may do so and in that case the specific value can be specified.

In the default case, ATS configuration will automatically check for TPROXY support via the presence of the linux/in.h header file and compile in TPROXY support if it is available. If that fails, you may be able to recover by using one of the options above. Note that transparency may be built in by default but it is not active unless explicitly enabled in the ATS configuration files.