George:

Thanks for the feedback.  Your suggested change did in fact work, but
as you observe, it is less efficient than using ipset.


On Fri, 2017-12-15 at 03:29 +0100, Georges Racinet wrote:
> Hi,
> 
> As it turns out, I'm typing this on a system recently upgraded to
> F27,
> so I decided to install f2b and take a look. Thanks for noticing it
> has
> 0.10 for me ;-)
> 
> And long story short, I was initially convinced it'd rather be a
> remnant
> of something weird on your system, but I reproduce the issue, and I
> think it's a bug in (that version of) f2b's use of ipset with ipv6
> (at
> least in firewalld context).
> 
> To workaround the issue you may simply edit
> /etc/fail2ban/jail.d/00-firewalld.conf, replacing 'firewallcmd-ipset' 
> by
> 'firewallcmd-multiport', it worked for me.
> 
> Edit: while checking what the output of 'ipset list' would be for
> sets
> of IPv6 addresses, I got this in my search results
> https://github.com/fail2ban/fail2ban/issues/1990, which is fixed, and
> looks to be the same bug without ip6tables-restore (optional backend
> of
> firewalld).
> 
> Time for me to see how to use this package with nftables on Fedora…
> 
> On 12/13/2017 06:40 PM, Daniel L. Srebnick wrote:
> > I just upgraded Fedora to FC27, which includes the IPv6 capable
> > fail2ban (0.10.0).
> > 
> > IPv6 addresses are not being blocked because of an issue when f2b
> > calls
> > ip6tables:
> > 
> > Dec 13 12:36:14 myhost.com firewalld[1026]: WARNING:
> > '/usr/sbin/ip6tables-restore --wait=2 -n' failed:
> > Dec 13 12:36:14 myhost.com firewalld[1026]: ERROR: COMMAND_FAILED
> 
> It turns out that indeed firewalld uses the lower level
> iptables-apply/restore utilities (a fact I didn't know)
> By turning on firewalld debug log at level >=3, one can see what it
> tried to load with ip6tables-restore:
> 
>     2017-12-15 02:31:08 DEBUG1: direct.addRule('ipv6', 'filter',
> 'INPUT', 0,
> '-p','tcp','-m','multiport','--dports','ssh','-m','set','--match-
> set','f2b-sshd6','src','-j','REJECT','--reject-with','icmp6-port-
> unreachable')
>     2017-12-15 02:31:08 DEBUG2: <class
> 'firewall.core.ipXtables.ip6tables'>: /usr/sbin/ip6tables-restore
> /run/firewalld/temp.pxn873ip: 146
>            1: *filter
>            2: -I INPUT_direct 1 -p tcp -m multiport --dports ssh -m
> set
> --match-set f2b-sshd6 src -j REJECT --reject-with icmp6-port-
> unreachable
>            3: COMMIT
> 
> Now I tried the same directly to get a grasp :
> 
>     $ sudo ip6tables -I INPUT_direct 1 -p tcp -m multiport --dports
> ssh
> -m set --match-set f2b-sshd6 src -j REJECT --reject-with
> icmp6-port-unreachable
> 
>     ip6tables v1.6.1: The protocol family of set f2b-sshd6 is IPv4,
> which is not applicable.
> 
> And indeed :
> 
> $ sudo ipset list
>     Name: f2b-sshd6
>     Type: hash:ip
>     Revision: 4
>     Header: family inet hashsize 1024 maxelem 65536 timeout 600
>     Size in memory: 88
>     References: 0
>     Number of entries: 0
>     Members:
> 
> > 
> > Seems to be that the "--wait" parameter is not supported by
> > ip6tables-
> > restore.
> 
> It says so, but it behaves like a mere warning.
> 
> Regards,
> 
> > _______________________________________________
> > Fail2ban-users mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/fail2ban-users
> 
> 
> 
> 
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