This is a quick and fairly dirty high performance DNS resolution tool, designed for quick overview MX surveying.
It reads a table in a postgresql database that has at least two columns, one containing domain names and the other a result column initially containing NULLs. For each domain name it resolves the MX record, then writes one of the highest-priority MXes into the result column.
It will run many DNS resolutions in parallel (5000) by default, and will put a high load on the recursive resolver it uses. It's intended to use a dedicated recursive resolver, so is currently hardwired to send queries via 127.0.0.1.
dbdnsresolve --help will display all the supported commandline flags.
dbdnsresolve --table=<tablename> --domain=<column> --result=<column> is
the minimum required set of options.
Build with "make", install to /usr/local/bin with "sudo make install".
Prerequisites are adns, libpqxx version 4 or later, gflags and a reasonably recent boost installation.