Hello,

In this new year, apart from wishing you all the best, I would also like to share with you the anomalies I was able to raise in Ipfire on the generation of firewall rules using the HMI.

I noticed 3 major problems in the management of firewall rules.

In the page https://ipfire:444/cgi-bin/firewall.cgi, it is worth noting 3 tables, namely Firewall Rules, Incoming Firewall Access and Outgoing Firewall Access.

The first two deduplication concerns the rules established in the 1st table, Firewall Rules.

1e problem :

By defining a FORWARD rule whose destination is the standard network red0 (everything but green0/orange0/blue0/etc...), a rule is created in FORWARDFW.

 

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 However, I noticed that also that these same rules were reported in INPUTFW

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INPUTFW rules with the -o red0 flag, it feels weird, doesn't it?

 

2nd problem :

 

It is much more delicate because it concerns DNAT.

For the creation of such a rule, here is the example below.

 

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Including the 4 redirection rules :

 

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As we can see, they are correctly created in NAT_DESTINATION :

 

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However, it is not expected to be duplicated in OUTGOINGFW as well.

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 In fact, the creation of these rules is useless, even dangerous. Hopefully things are going well at home and the potential threat remains my person (LOL).

 

The last case is a little more twisted, it concerns the SNAT, of which here is the example below.

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As I was refused a nice creation :

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I modified directly in the /var/ipfire/firewall/input file.

 

Here is the result:

 

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Using such a rule allows me to follow the path represented by the diagram below and solve the problem of double NAT:

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The rules are correctly created in table NAT_SOURCE.

 

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However, there is also a rule creation in the INPUTFW table, which I think is unnecessary.

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Awaiting your thoughts, I hope I have provided all the information you need to understand the 3 cases above.

With kind regards.

Jbsky