How do I protect my machine from attack?
The most important thing is to download Bitcoin Core from the correct destination. You can download it from bitcoincore.org or the source code can be found on the Bitcoin Core GitHub repo. If you download it from a malicious party’s destination you could have serious problems. Luke Dashjr has a blog post on the extra precautions you could follow to make sure you are installing the correct software but this may be a challenge for you if you aren’t technical.
Do I install specific security software?
No there is no specific security software to install. Depending on your operating system some may recommend an antivirus software but that is general security hygiene not specific to Bitcoin.
As I understand it, my IP address will be visible to see.
Yes your IP address will be visible to peers that you connect to unless you use Tor. (Tor is recommended if privacy is especially important to you.) However, if you choose to use a clearnet node and you don’t want your IP address to show up on sites like bitnodes.io you can run a non-listening node by disabling listening. You do this by configuring with the
-listen=0 flag or putting
listen=0 in your config file. This way you can’t be contacted by nodes you aren’t directly connected to. The downside to this is that you aren’t helping the network as much and you will typically have fewer connections.