Re: NAT problems 14.3+

Update, LS

Upgraded one of the test machines  machine from 14.4 to 15.0-RELEASE but =
the ipfw ruleset with skipto for nat still has an issue. When i ping =
(ping 1.1.1.1) from a jail to the outside world, within seconds the =
counters ramp up on the skipto line for udp(?)

00106 176633247 9008295597 Wed May  6 12:23:25 2026 skipto 1000 udp from =
10.10.2.0/24 to any out via ice0 keep-state :default

And this is regardless of having txcsum/rxcsum enabled or disabled on =
interfaces. And shortly after the host machine is unresponsive and =
basically crashed.=20

Using a simplified nat capable ipfw ruleset not using skipto lines, =
works as expected still.=20

> On 5 May 2026, at 20:41, Rob Bloemers <[email protected]> wrote:
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> Hi!
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> No the hosts are all bare metal in my tests/environments.=20
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>> On 5 May 2026, at 19:08, Miroslav Lachman <[email protected]> wrote:
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>> On 05/05/2026 16:45, Rob Bloemers wrote:
>>> I found the reason, or better put, workaround for my issue. When =
disabling tx and rxcsum on the vnet internet of the jail, things starts =
to work again.
>> Any chance your host is running as z VM inside some hypervisor? I had =
this problem in the past on KVM guest.
>> Network is working fine for host, but not for another guest behind =
this gateway with NAT until I disabled rx / tx sum on FreeBSD host's =
interface.
>>=20
>> M. Lachman
>>=20
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