On 06.01.2021 16:50, Stefan Schantl wrote:
Hello Matthias,
Hi Stefan,
in general I like the possibility to force the usage of the local DNS server by just redirecting all queries to it. This is way more elegant instead of blocking the requests to any nameservers by firewall rules, except the local unbound to force it's usage.
I reviewed your last patch and want to give you some thoughts - may the can help you:
...
For me - and of course for everybody who uses IPSec or QoS - this is a showstopper. Saving the affected - temporary rules - is too complicated (for me). I'm trying to make this as simple as possible.
Yes, this is the reason, why reloading / restarting the whole firewall should be avoided if possible.
I completely dropped this - got a new solution which works, but it could be better. It still uses a new init-file as mentioned below.
So I'm thinking about separating the DNS/NTP-commands and use them in a another init-file, apart from the firewall initscript. I just want to "go out of the way". ;-)
As I see it, IPSec and QoS (e.g) would not be affected and furthermore we would perhaps have the choice to control some other settings through this file. E.g., the settings from '/var/ipfire/optionsfw/settings' are processed in various control files, see: https://community.ipfire.org/t/forcing-all-dns-traffic-from-the-lan-to-the-f...
And perhaps that would give us the chance to tidy things up. Just a thought.
So what about using an 'optionsfw' initscript for the DNS/NTP rules?
This would be a possible solution, but ends in multiple files which are doing the same - dealing with firewall rules.
Ok. Thats right. I'm now using a new '/etc/rc.d/init.d/dnsntp'-file for this, but...:
This is not very intuitive and hard to maintain.
Ok. I see your point.
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The only affected chain is CUSTOMPREROUTING, so other functionalities/chains (IPSec, QoS) should not be affected.
Please do not use one of the CUSTOM firewall chains, they only should be used by the users to customize their systems.
I would suggest to use a new chain like "FORCEDREDIRECT" or similar before the CUSTOMPREROUTING chain.
I see two possibilities doing this in '/etc/rc,d/init.d/firewall'.
Inserting at line 169:
... iptables -t nat -N FORCEREDIRECT iptables -t nat -A PREROUTING -j FORCEREDIRECT iptables -t nat -N CUSTOMPREROUTING iptables -t nat -A PREROUTING -j CUSTOMPREROUTING ...
Or after (e.g): ... # Added for DNS REDIRECTS iptables -t nat -N FORCEREDIRECTS iptables -t nat -I PREROUTING 1 -j FORCEREDIRECTS ...
Am I right doing it this way?
This would have the advantage, that you safely can flush this chain and directly can insert you redirect rules for the network zones and desired the protocol. So you not need to check each time if the rule already exists.
This will speeds up the whole process and keeps the code clear.
Makes sense. Thanks for the hints.
Instead of writing an additional init script for adding the rules you directly can execute the iptables calls by your new optionsfw binary.
I didn't do this before: I'll take a look.
This allows you to easily call the binary from the CGI file and perform all required operations inside the single chain without touching anything else on the running firewall.
Yep. I see. Good point. Thanks again. ;-)
Best, Matthias