Hi,
according to the screenshots, you are running Core Update 108, which was released in 2016 (see release announcement for details).
Just for the records: We, the IPFire development team, strongly recommend to install a freshly downloaded ISO from https://www.ipfire.org/ (do not use any ISOs provided by 3rd parties and make sure you have verified the checksum). Core Update 108 is more than just heavily outdated - setting up a firewall on a basis like this is, if I might put it that way, beyond stupid.
Please install the latest Core Update (avoid 32 bit, if possible) and come back again if things do not work afterwards.
Please refer to the documentation for further information regarding DNS settings.
Thanks, and best regards,
Peter Müller