I have been using iptables on Fedora for about 2 years to keep out unwanted servers/data collectors. The number of lines is now hundreds. Until 1 week ago no problems and no changes in the firewall. 2 days ago (July 19) I had, even without a firewall on Fedora, selective access to google for example, but not to duckduckgo and most of various sites. For example, access to nu.nl, but random searches were not carried out. I did the test using USB sticks with which I started Linux Mint and Fedora 44 alternately without a firewall, with the same result. Fedora didn’t work, Linux Mint did. Here is a brief configuration. Laptop, 16 Gb internal memory, internet via Starlink, no virus scanner, iptables via xxx.sh. No special things in the firewall rules, bios; all systems default. checking data traffic with sniffnet.app.
Internet via mobile or Starlink; the same result.
example firewall rule:
sudo ip(6)tables -I OUTPUT -s xxxxxxxx -j DROP
sudo ip(6)tables -I INPUT -s xxxxxx -j DROP
The iptables can be initialized at boot time by the services ip6tables.service and iptables.service. A user can chose to use that instead of firewalld.
Note that the package iptables-nft will allow you to use iptables and its syntax with nftables.
Yes, I understand that iptables has been deprecated for a while, but some folks have extensive iptables rules that would be complicated/a lot of work to translate to nftables and test , even with automated tools.
That’s not to say such a migration is a bad idea (quite the contrary, in fact), but it would be much better for such migrated rule sets to be fully tested and vetted first IMHO.