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<base href="https://bugzilla.netfilter.org/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - The Check option of iptables does not work as expected"
href="https://bugzilla.netfilter.org/show_bug.cgi?id=1408">1408</a>
</td>
</tr>
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<th>Summary</th>
<td>The Check option of iptables does not work as expected
</td>
</tr>
<tr>
<th>Product</th>
<td>nftables
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>arm
</td>
</tr>
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<th>OS</th>
<td>Ubuntu
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>minor
</td>
</tr>
<tr>
<th>Priority</th>
<td>P5
</td>
</tr>
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<th>Component</th>
<td>iptables over nftable
</td>
</tr>
<tr>
<th>Assignee</th>
<td>pablo@netfilter.org
</td>
</tr>
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<th>Reporter</th>
<td>ed@kapitein.org
</td>
</tr></table>
<p>
<div>
<pre>when checking if a dnat rule exist ( with the --check option ) the
--to-destination is not checked correctly.
i have a rule:
pkts bytes target prot opt in out source destination
1 44 DNAT tcp -- * * 0.0.0.0/0 0.0.0.0/0
tcp dpt:80 to:192.168.59.43:80
if i check if the rule exists, the exit code is 0, as expected:
sudo iptables -t nat -C PREROUTING --proto tcp --dport 80 -j DNAT
--to-destination 192.168.59.43:80; echo $?
0
however, if i change the -to-destination to a bogus value,
the check still returns 0, and that is unexpected:
sudo iptables -t nat -C PREROUTING --proto tcp --dport 80 -j DNAT
--to-destination 1.2.3.4:5; echo $?
0
if i change the protocol from tcp to udp the check fails, as expected:
sudo iptables -t nat -C PREROUTING --proto udp --dport 80 -j DNAT
--to-destination 192.168.59.43:80; echo $?
iptables: Bad rule (does a matching rule exist in that chain?).
1
Is there a way to check the -to-destination also?
Some info on the environment:
Version: iptables v1.8.2 (nf_tables)
OS: raspbian buster
Kernel: Linux blahblah 4.19.93-v7+ #1290 SMP Fri Jan 10 16:39:50 GMT 2020
armv7l GNU/Linux
Platform: raspberry pi 3B+</pre>
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