Date: Wed, 9 Mar 2016 11:24:41 -0800 (PST) From: Don Lewis <truckman@FreeBSD.org> To: fjwcash@gmail.com Cc: freebsd-ipfw@freebsd.org Subject: Re: ipwf dummynet vs. kernel NAT and firewall rules Message-ID: <201603091925.u29JOfQE011384@gw.catspoiler.org>
next in thread | raw e-mail | index | archive | help
On 9 Mar, Don Lewis wrote:
> On 9 Mar, Freddie Cash wrote:
>> On Wed, Mar 9, 2016 at 10:09 AM, Don Lewis <truckman@freebsd.org> wrote:
>>
>>> On 9 Mar, Franco Fichtner wrote:
>>> > Hi Don,
>>> >
>>> > If you mean pf(4)-based NAT, there is a patch that originates from
>>> > m0n0wall that handles the transition. We're using it in OPNsense
>>> > for that reason. Here is the patch for 10.x, maybe that is what
>>> > you're looking for:
>>>
>>> Nope, I'm using ipfw in-kernel NAT, which is not the default in
>>> rc.firewall, but is easy to paste in next to or in place of the default
>>> natd configuration.
>>>
>>> case ${firewall_nat_enable} in
>>> [Yy][Ee][Ss])
>>> if [ -n "${firewall_nat_interface}" ]; then
>>> if echo "${firewall_nat_interface}" | \
>>> grep -q -E '^[0-9]+(\.[0-9]+){0,3}$'; then
>>> firewall_nat_flags="ip
>>> ${firewall_nat_interface} ${firewall_nat_flags}"
>>> else
>>> firewall_nat_flags="if
>>> ${firewall_nat_interface} ${firewall_nat_flags}"
>>> fi
>>> ${fwcmd} nat 123 config log ${firewall_nat_flags}
>>> ${fwcmd} add nat 123 ip4 from any to any via
>>> ${firewall_nat_interface}
>>> fi
>>> ;;
>>> esac
>>>
>>> My suspicion is that if a packet matches the rule to pass it to dummynet
>>> that it is bypassing NAT.
>>> _______________________________________________
>>> 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"
>>>
>>
>> ?Do you have the sysctl net.inet.ip.fw.one_pass set to 0 or 1?
>
> Aha, I've got it set to 1.
>
>> If set to 1, the a dummynet match ends the trip through the rules, and the
>> packet never gets to the NAT rules. Or, if a NAT rule matches, the trip
>> through the rules ends, and it never get to the dummynet rules. Depending
>> on which you have first.
>
> Dummynet is first.
>
>> You'll need to set net.inet.ip.fw.one_pass?=0 in order to re-inject the
>> packet into the rules after it matches a dummynet or NAT rule. Or, do the
>> NAT and dummynet rules on different interfaces to match different traffic.
>
> How do I prevent the re-injected packets from being sent back into
> dummynet? My NAT rule looks like it could have the same problem, but
> that looks fixable.
I just read the fine man page and is says that after re-injection the
packet starts with the next rule ... cool!
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201603091925.u29JOfQE011384>