Date: Thu, 10 Mar 2016 12:29:23 -0800 From: Julian Elischer <julian@freebsd.org> To: Don Lewis <truckman@FreeBSD.org>, freebsd-ipfw@freebsd.org Subject: Re: ipwf dummynet vs. kernel NAT and firewall rules Message-ID: <56E1D923.6060405@freebsd.org> In-Reply-To: <201603091733.u29HX05o011028@gw.catspoiler.org> References: <201603091733.u29HX05o011028@gw.catspoiler.org>
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On 9/03/2016 9:32 AM, Don Lewis wrote: > I'm trying to add FQ-CoDEL AQM to my FreeBSD 10 firewall box using this > patch: <http://caia.swin.edu.au/freebsd/aqm/downloads.html>, but I'm > running into a problem that I think is caused by an interaction between > in-kernel NAT and dummynet. I've set up two dummynet pipe/sched/queue > instances using example 3.3a from this document > <http://caia.swin.edu.au/freebsd/aqm/patches/README-0.1.txt> with the > appropriate bandwidths, but otherwise default tunings to shape both > inbound and outbound traffic. My inside network is a /24 and I have an > external /29 (ext/29) network that I don't want to rate limit. My > outside network interface is re0. I'm using the /etc/rc.firewall > "simple" firewall configuration. > > The problem that I'm having crops up when I actually try to add the > firewall rules to select the traffic that I want to rate limit. The > first rule in the list is: > 100 allow ip from any to any via lo0 > The second rule is numbered 200 and is first anti-spoofing rule. If > I add *either* of these two rules, then I'm no longer able to > communicate between hosts on my internal network and the rest of the > world: > > ipfw 110 add queue 1 ip from not ext/29 to any in recv re0 > ipfw 120 add queue 2 ip from any to not ext/29 out xmit re0 > > It seems like the inbound rule should be early in the rule list so that > any inbound traffic that gets dropped by the firewall rules gets counted > even if it is dropped by later rules. It also seems like the outbound > rule needs to be before any allow rules since an allow rule would skip > the remaining rules and would not count that traffic. Unfortunately the > ipfw documentation doesn't really describe the interaction between > dummynet, NAT, and other firewall rules. > > Unfortunately this is a live system, so it is difficult to do controlled > experiments and look at the ipfw counters to see where things might be > going into the weeds ... ok so you need to do what I always tell people.. split your rules into separate incoming and outgoing rule sets. so your first rule should be: skipto 10000 all from any to any in. and have separate sets of rules for incoming and outgoing packets. Then you should always set one_pass to 0 and expect your packets to come back to the firewall at the next number. > > _______________________________________________ > freebsd-ipfw@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-ipfw > To unsubscribe, send any mail to "freebsd-ipfw-unsubscribe@freebsd.org" >
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