we have exporters for both.
IP.Board
https://github.com/akhoury/nodebb-plugin-import-ipboard
VBulletin
https://github.com/akhoury/nodebb-plugin-import-vbulletin
you don't really need to install any of these 2, just install
migrate your old crappy forum to NodeBB. Contribute to akhoury/nodebb-plugin-import development by creating an account on GitHub.
faviconGitHub (github.com)
and use the interface the select the right exporter.
Note: hold off a little bit on the source forum with 2M+ posts, I am still in the process of resolving some memory issues