There's a closed pull request on the void-packages repository

iptables: adjust run scripts for more configuration flexibility
https://github.com/void-linux/void-packages/pull/31145

Description:
The single configuration file approach that the iptables services
provide precludes using it in more complicated buildouts such as ones
defined with config management tools. This change takes a hybrid
approach of the old method (to preserve backwards compatibility, etc)
and the method taken with void-ansible-roles/network.

Changes:
No longer flush tables prior to loading new data - rely on finish in all
  cases
Load data from /etc/iptables/iptables.rules and all found
  /etc/iptables.d/\*.rules
Ditto ip6 equivalents (ip6rules.rules, ip6tables.d/\*.{,6}rules)
Flush nat table in both v4 and v6 mode (nat table supported on v6 since
  kernel 3.7)

Caveats: the ip6tables.d match is overly explicit since dash does not
provide brace expansion and there is no particularly clean way to match
a single character or empty when expanding globs.

@ailiop-git 
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#### General
- [ ] This is a new package and it conforms to the [quality requirements](https://github.com/void-linux/void-packages/blob/master/Manual.md#quality-requirements)

#### Have the results of the proposed changes been tested?
- [x] I use the packages affected by the proposed changes on a regular basis and confirm this PR works for me
- [ ] I generally don't use the affected packages but briefly tested this PR

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#### Does it build and run successfully? 
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- [ ] I built this PR locally for these architectures (if supported. mark crossbuilds):
  - [ ] aarch64-musl
  - [ ] armv7l
  - [ ] armv6l-musl