Date: Tue, 25 Jul 2017 18:38:51 +0300 From: "Andrey V. Elsukov" <bu7cher@yandex.ru> To: "Muenz, Michael" <m.muenz@spam-fetish.org>, freebsd-net@freebsd.org Subject: Re: NAT before IPSEC - reply packets stuck at enc0 Message-ID: <e870fe5e-431c-49b6-5960-123d0c7be0a9@yandex.ru> In-Reply-To: <0bbf5bb9-8089-f9ce-3b1d-e9bcbdbc6c76@spam-fetish.org> References: <459d59f7-2895-8aed-d547-be46a0fbb918@spam-fetish.org> <911903d1-f353-d5d6-d400-d86150f88136@yandex.ru> <2d607e1a-a2c0-0f85-1530-c478962a76cd@spam-fetish.org> <3344e189-cdf0-a2c9-3a2a-645460866f2d@yandex.ru> <1279753e-9ad1-2c02-304e-5001e2bbc82f@spam-fetish.org> <15e6eb38-ef0c-7bfd-5f2c-d2acc8ea1af4@yandex.ru> <cdb7e172-4074-4559-1e91-90c8e9276134@spam-fetish.org> <63e80fcf-915e-2dd5-d8c9-1904c8261c6f@yandex.ru> <1c91cd8f-105d-e886-3126-67505c6c3900@spam-fetish.org> <c738380c-e0cc-2d32-934e-a05502887b93@yandex.ru> <1e889acf-49d1-b70f-7097-82e6e4dfabb6@spam-fetish.org> <454ed1b7-a80f-b096-cfa1-3c32d1e60f7d@yandex.ru> <f4c5a11c-a329-d746-ece8-e3752a6c82ea@spam-fetish.org> <5dfdfbb3-1046-5abe-b23a-b62c215b5d08@yandex.ru> <ada882bb-7344-49c5-0e47-e1432f27f1c9@spam-fetish.org> <860b48aa-b99e-7b71-3724-587ee0a7fe80@spam-fetish.org> <1b831b84-1d3f-38cb-acee-07a339315417@yandex.ru> <0bbf5bb9-8089-f9ce-3b1d-e9bcbdbc6c76@spam-fetish.org>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --UOXTRanMpkUPuc85obSMXmjMn7ps3B6tB Content-Type: multipart/mixed; boundary="La8rlHWCDGBFpEd4FhTXQGmhTlIUR1Cv4"; protected-headers="v1" From: "Andrey V. Elsukov" <bu7cher@yandex.ru> To: "Muenz, Michael" <m.muenz@spam-fetish.org>, freebsd-net@freebsd.org Message-ID: <e870fe5e-431c-49b6-5960-123d0c7be0a9@yandex.ru> Subject: Re: NAT before IPSEC - reply packets stuck at enc0 References: <459d59f7-2895-8aed-d547-be46a0fbb918@spam-fetish.org> <1c0de616-91ff-a6f9-d946-f098bc1a709f@spam-fetish.org> <911903d1-f353-d5d6-d400-d86150f88136@yandex.ru> <2d607e1a-a2c0-0f85-1530-c478962a76cd@spam-fetish.org> <3344e189-cdf0-a2c9-3a2a-645460866f2d@yandex.ru> <1279753e-9ad1-2c02-304e-5001e2bbc82f@spam-fetish.org> <15e6eb38-ef0c-7bfd-5f2c-d2acc8ea1af4@yandex.ru> <cdb7e172-4074-4559-1e91-90c8e9276134@spam-fetish.org> <63e80fcf-915e-2dd5-d8c9-1904c8261c6f@yandex.ru> <1c91cd8f-105d-e886-3126-67505c6c3900@spam-fetish.org> <c738380c-e0cc-2d32-934e-a05502887b93@yandex.ru> <1e889acf-49d1-b70f-7097-82e6e4dfabb6@spam-fetish.org> <454ed1b7-a80f-b096-cfa1-3c32d1e60f7d@yandex.ru> <f4c5a11c-a329-d746-ece8-e3752a6c82ea@spam-fetish.org> <5dfdfbb3-1046-5abe-b23a-b62c215b5d08@yandex.ru> <ada882bb-7344-49c5-0e47-e1432f27f1c9@spam-fetish.org> <860b48aa-b99e-7b71-3724-587ee0a7fe80@spam-fetish.org> <1b831b84-1d3f-38cb-acee-07a339315417@yandex.ru> <0bbf5bb9-8089-f9ce-3b1d-e9bcbdbc6c76@spam-fetish.org> In-Reply-To: <0bbf5bb9-8089-f9ce-3b1d-e9bcbdbc6c76@spam-fetish.org> --La8rlHWCDGBFpEd4FhTXQGmhTlIUR1Cv4 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 25.07.2017 17:06, Muenz, Michael wrote: >> As I said already, the NAT thinks that both packets are inbound and do= es >> translation for source address each time. You need to do translation f= or >> both directions on enc0 interface like I described, or you need to >> somehow hack/modify ipfw_nat. >> >> You do not need to create SA for 10.26.2.0->10.24.66.0, you only need >> create security policy, that will "route" such packets into the IPsec >> tunnel. The translation will be done inside IPsec before IP >> encapsulation and encryption. Since you are using tunnel mode IPsec, >> replies will be returned to your external IP address, and this SA is >> exists already. After decryption and IP decapsulation the destination >> address of packet will be translated back to 10.26.2.N on if_enc(4). >=20 > Can I use this spdadd command also when using strongswan? (Please excus= e > stupid questions) I'm not familiar with strongswan configuration, but you can just try and check that the proposed configuration will work. >> ipfw nat 1 config ip 10.26.1.1 log >> ipfw add 179 nat 1 all from 10.26.2.0/24 to 10.24.66.0/24 out xmit enc= 0 >> ipfw add 179 nat 1 all from 10.24.66.0/24 to 10.26.1.1 in recv enc0 >> >=20 > Ok so your 3 nat commands will only match when there's a new spd like > above right? > Since there's nothing on enc0 without it. Yes, it is. A security policy will route requests from 10.26.2.0/24 into IPsec tunnel, where they should be translated, and then replies will be received. --=20 WBR, Andrey V. Elsukov --La8rlHWCDGBFpEd4FhTXQGmhTlIUR1Cv4-- --UOXTRanMpkUPuc85obSMXmjMn7ps3B6tB Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEzBAEBCAAdFiEE5lkeG0HaFRbwybwAAcXqBBDIoXoFAll3ZgsACgkQAcXqBBDI oXr3dggAwKt+Yt/s/73yQbhakUfuuUpqGkFqtfBhkWupSAxgqFd/frulKm9kcr6L DzQhdHWD6PARq/aaiJQRpaTjmjhPWeZUEoQBlrXX74kC/BAidHkPSN+W19A7jGsV CTfA4xA5tb5holOulYgRuR7591d9zIW2FL5cj8rLuLJe9FJgN2og67Tgfi5mynBO OiqkoTfNJ+TNqndRsaJNZjTURgW6PJ+xm8HmQWBGBBYLoKAklpotsOaDikb31xVp gBVa6qLqiZjTqjzfGkfaJQX2j6MdZr/D5XyixdsON9O6YaULu2/RU3e5yRqmfcW1 tGjrO83i5S5cQp3V7bFHk46tiyhBLQ== =1kw6 -----END PGP SIGNATURE----- --UOXTRanMpkUPuc85obSMXmjMn7ps3B6tB--
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