Re: pf isakmpd: NAT through encryption interface?
On Wed, 28 Jun 2006, Stephen Bosch wrote: Hi, Roy: Roy Morris wrote: Yes it does work! I guess I better hold on to these two boxes I have. Seems they are the only ones that do! lol I have A. clients on each end behind a vpn/pf box B. enc0 binat from internal client to public IP of other side client C. /etc/hostname.if alias for the binat IP D. isakmpd.conf uses public IP (A) for phase 1, and (B internal client nat) for phase 2 I've had a closer look at this... In my case, the other peer expects a private IP on my internal network. Your directions involve an alias. Do I need this alias? Can I not just nat on the encryption interface like so? nat on $enc_if from $internal_ip to $remote_internal_ip - $private_nat_address? This is really confusing me. -Stephen- If you do nat on $enc_if your incoming packets will not match an existing IPSEC flow and will never get routed to your enc0 interface in the first place. man ipsec shows a flow diagram of how packets move in the kernel -Matt-
Re: pf isakmpd: NAT through encryption interface?
Hi, Roy: Roy Morris wrote: Yes it does work! I guess I better hold on to these two boxes I have. Seems they are the only ones that do! lol I have A. clients on each end behind a vpn/pf box B. enc0 binat from internal client to public IP of other side client C. /etc/hostname.if alias for the binat IP D. isakmpd.conf uses public IP (A) for phase 1, and (B internal client nat) for phase 2 I've had a closer look at this... In my case, the other peer expects a private IP on my internal network. Your directions involve an alias. Do I need this alias? Can I not just nat on the encryption interface like so? nat on $enc_if from $internal_ip to $remote_internal_ip - $private_nat_address? This is really confusing me. -Stephen- Have you actually tried it? nat on enc0 from $ip_to_be_changed to $peer_net - $nat_ip
pf isakmpd: NAT through encryption interface?
Imagine the following scenario: You have two VPN endpoints. One is an OpenBSD system running isakmpd and pf, the other is a VPN concentrator from some vendor. The OpenBSD already has other VPNs set up, all using the same internal network. Renumbering isn't going to work. The VPN concentrator operator has an internal addressing scheme he insists other endpoints conform to. The question, then: Is it even possible to NAT through an encryption interface? For example: OpenBSD internal network: 192.168.45.0/24 Network other guy would prefer OpenBSD use: 10.110.40.0/24 Network other guy is using: 10.110.10.0/24 The command might look like this: nat on $enc_if from 192.168.45.0:network to 10.110.10.0:network - 10.110.40.10 Forgive me if this i) is impossible, ii) is crazy, iii) the syntax of the command is wrong. I'd rather run it past the list than tinker on production equipment. Thanks for any help and advice, -Stephen-
Re: pf isakmpd: NAT through encryption interface?
Stephen Bosch wrote: Imagine the following scenario: You have two VPN endpoints. One is an OpenBSD system running isakmpd and pf, the other is a VPN concentrator from some vendor. The OpenBSD already has other VPNs set up, all using the same internal network. Renumbering isn't going to work. The VPN concentrator operator has an internal addressing scheme he insists other endpoints conform to. The question, then: Is it even possible to NAT through an encryption interface? For example: OpenBSD internal network: 192.168.45.0/24 Network other guy would prefer OpenBSD use: 10.110.40.0/24 Network other guy is using: 10.110.10.0/24 The command might look like this: nat on $enc_if from 192.168.45.0:network to 10.110.10.0:network - 10.110.40.10 Forgive me if this i) is impossible, ii) is crazy, iii) the syntax of the command is wrong. I'd rather run it past the list than tinker on production equipment. Thanks for any help and advice, -Stephen- blind leading the blind here but This was recently discussed, and it was pointed out that the decision to encrypt happens before the nat-ing. I deal with this self same issue by the lazy expedient of a firewall with a vpn server that has one interface in the dmz and one on the public net. So I do the vendor mandated nat-ing and pass to the vpn server. This made writing the pf rules for both sets of machines pretty straight forward.
Re: pf isakmpd: NAT through encryption interface?
Dag Richards wrote: Stephen Bosch wrote: Imagine the following scenario: You have two VPN endpoints. One is an OpenBSD system running isakmpd and pf, the other is a VPN concentrator from some vendor. The OpenBSD already has other VPNs set up, all using the same internal network. Renumbering isn't going to work. The VPN concentrator operator has an internal addressing scheme he insists other endpoints conform to. The question, then: Is it even possible to NAT through an encryption interface? For example: OpenBSD internal network: 192.168.45.0/24 Network other guy would prefer OpenBSD use: 10.110.40.0/24 Network other guy is using: 10.110.10.0/24 The command might look like this: nat on $enc_if from 192.168.45.0:network to 10.110.10.0:network - 10.110.40.10 Forgive me if this i) is impossible, ii) is crazy, iii) the syntax of the command is wrong. I'd rather run it past the list than tinker on production equipment. Thanks for any help and advice, -Stephen- blind leading the blind here but This was recently discussed, and it was pointed out that the decision to encrypt happens before the nat-ing. Correct me if I am wrong, then -- this should work. I should be able to set up a NAT rule that will affect encrypted traffic in the way I want. Someone mentioned to me that this does work in 3.9. Will it work in 3.8? That's what our gear is running. -Stephen-
Re: pf isakmpd: NAT through encryption interface?
Stephen Bosch wrote: Dag Richards wrote: Stephen Bosch wrote: Imagine the following scenario: You have two VPN endpoints. One is an OpenBSD system running isakmpd and pf, the other is a VPN concentrator from some vendor. The OpenBSD already has other VPNs set up, all using the same internal network. Renumbering isn't going to work. The VPN concentrator operator has an internal addressing scheme he insists other endpoints conform to. The question, then: Is it even possible to NAT through an encryption interface? For example: OpenBSD internal network: 192.168.45.0/24 Network other guy would prefer OpenBSD use: 10.110.40.0/24 Network other guy is using: 10.110.10.0/24 The command might look like this: nat on $enc_if from 192.168.45.0:network to 10.110.10.0:network - 10.110.40.10 Forgive me if this i) is impossible, ii) is crazy, iii) the syntax of the command is wrong. I'd rather run it past the list than tinker on production equipment. Thanks for any help and advice, -Stephen- blind leading the blind here but This was recently discussed, and it was pointed out that the decision to encrypt happens before the nat-ing. Correct me if I am wrong, then -- this should work. I should be able to set up a NAT rule that will affect encrypted traffic in the way I want. Someone mentioned to me that this does work in 3.9. Will it work in 3.8? That's what our gear is running. -Stephen- Um no, it wont work. Once the traffic is encrypted you will no longer be able to nat it. The original packet is now and encrypted blob that is the payload of a new packet with a source of your gateway and dest their GW. you can nat the wrapper packet but not the payload. I have 2x ibm x series somethings for fw's, and 2x hp dl360s for vpn servers all running 3.9.
Re: pf isakmpd: NAT through encryption interface?
Stephen Bosch wrote: Dag Richards wrote: Stephen Bosch wrote: Imagine the following scenario: You have two VPN endpoints. One is an OpenBSD system running isakmpd and pf, the other is a VPN concentrator from some vendor. The OpenBSD already has other VPNs set up, all using the same internal network. Renumbering isn't going to work. The VPN concentrator operator has an internal addressing scheme he insists other endpoints conform to. The question, then: Is it even possible to NAT through an encryption interface? For example: OpenBSD internal network: 192.168.45.0/24 Network other guy would prefer OpenBSD use: 10.110.40.0/24 Network other guy is using: 10.110.10.0/24 The command might look like this: nat on $enc_if from 192.168.45.0:network to 10.110.10.0:network - 10.110.40.10 Forgive me if this i) is impossible, ii) is crazy, iii) the syntax of the command is wrong. I'd rather run it past the list than tinker on production equipment. Thanks for any help and advice, -Stephen- blind leading the blind here but This was recently discussed, and it was pointed out that the decision to encrypt happens before the nat-ing. Correct me if I am wrong, then -- this should work. I should be able to set up a NAT rule that will affect encrypted traffic in the way I want. Someone mentioned to me that this does work in 3.9. Will it work in 3.8? That's what our gear is running. -Stephen- Um no, it wont work. Once the traffic is encrypted you will no longer be able to nat it. The original packet is now and encrypted blob that is the payload of a new packet with a source of your gateway and dest their GW. you can nat the wrapper packet but not the payload. I have 2x ibm x series somethings for fw's, and 2x hp dl360s for vpn servers all running 3.9. Yes it does work! I guess I better hold on to these two boxes I have. Seems they are the only ones that do! lol I have A. clients on each end behind a vpn/pf box B. enc0 binat from internal client to public IP of other side client C. /etc/hostname.if alias for the binat IP D. isakmpd.conf uses public IP (A) for phase 1, and (B internal client nat) for phase 2 (ip's changed to protect the innocent. No animals were harmed during this test) Jun 28 13:23:32.881298 (authentic,confidential): SPI 0x84adb14b: 222.222.222.111 111.111.111.111: 222.222.222.222.25247 111.111.111.222.80: S [tcp sum ok] 789729009:789729009(0) win 16384 mss 1460,nop,nop,sackOK,nop,wscale 0,nop,nop,timestamp 345218535 0 (DF) [tos 0x10] (ttl 63, id 29296, len 64) (DF) [tos 0x10] (ttl 63, id 44546, len 84) Jun 28 13:23:32.882822 (authentic,confidential): SPI 0xcf4b18fb: 111.111.111.111 222.222.222.111: 111.111.111.222.80 222.222.222.222.25247: S [tcp sum ok] 3946347346:3946347346(0) ack 789729010 win 16384 mss 1460,nop,nop,sackOK,nop,wscale 0,nop,nop,timestamp 1861954054 345218535 (DF) (ttl 63, id 35574, len 64) (DF) (ttl 64, id 12842, len 84, bad cksum 0!) Jun 28 13:23:32.883716 (authentic,confidential): SPI 0x84adb14b: 222.222.222.111 111.111.111.111: 222.222.222.222.25247 111.111.111.222.80: . [tcp sum ok] ack 1 win 17376 nop,nop,timestamp 345218535 1861954054 (DF) [tos 0x10] (ttl 63, id 31269, len 52) (DF) [tos 0x10] (ttl 63, id 34993, len 72) Jun 28 13:23:37.013444 (authentic,confidential): SPI 0x84adb14b: 222.222.222.111 111.111.111.111: 222.222.222.222.25247 111.111.111.222.80: F [tcp sum ok] 1:1(0) ack 1 win 17376 nop,nop,timestamp 345218543 1861954054 (DF) [tos 0x10] (ttl 63, id 30180, len 52) (DF) [tos 0x10] (ttl 63, id 61997, len 72) Jun 28 13:23:37.013716 (authentic,confidential): SPI 0xcf4b18fb: 111.111.111.111 222.222.222.111: 111.111.111.222.80 222.222.222.222.25247: . [tcp sum ok] ack 2 win 17376 nop,nop,timestamp 1861954062 345218543 (DF) (ttl 63, id 56710, len 52) (DF) (ttl 64, id 21978, len 72, bad cksum 0!) Jun 28 13:23:37.013806 (authentic,confidential): SPI 0xcf4b18fb: 111.111.111.111 222.222.222.111: 111.111.111.222.80 222.222.222.222.25247: F [tcp sum ok] 1:1(0) ack 2 win 17376 nop,nop,timestamp 1861954062 345218543 (DF) (ttl 63, id 40038, len 52) (DF) (ttl 64, id 19310, len 72, bad cksum 0!) Jun 28 13:23:37.014441 (authentic,confidential): SPI 0x84adb14b: 222.222.222.111 111.111.111.111: 222.222.222.222.25247 111.111.111.222.80: . [tcp sum ok] ack 2 win 17375 nop,nop,timestamp 345218543 1861954062 (DF) [tos 0x10] (ttl 63, id 838, len 52) (DF) [tos 0x10] (ttl 63, id 53227, len 72) Jun 28 13:23:38.749637 (authentic,confidential): SPI 0x84adb14b: 222.222.222.111 111.111.111.111: 222.222.222.222.40612 111.111.111.222.80: S [tcp sum ok] 402874189:402874189(0) win 16384 mss 1460,nop,nop,sackOK,nop,wscale 0,nop,nop,timestamp 345218547 0 (DF) [tos 0x10] (ttl 63, id 9220, len 64) (DF) [tos 0x10] (ttl 63, id 51268, len 84) Jun 28 13:23:38.749953 (authentic,confidential): SPI 0xcf4b18fb: 111.111.111.111
Re: pf isakmpd: NAT through encryption interface?
Roy Morris wrote: Stephen Bosch wrote: Dag Richards wrote: Stephen Bosch wrote: Imagine the following scenario: You have two VPN endpoints. One is an OpenBSD system running isakmpd and pf, the other is a VPN concentrator from some vendor. The OpenBSD already has other VPNs set up, all using the same internal network. Renumbering isn't going to work. The VPN concentrator operator has an internal addressing scheme he insists other endpoints conform to. The question, then: Is it even possible to NAT through an encryption interface? For example: OpenBSD internal network: 192.168.45.0/24 Network other guy would prefer OpenBSD use: 10.110.40.0/24 Network other guy is using: 10.110.10.0/24 The command might look like this: nat on $enc_if from 192.168.45.0:network to 10.110.10.0:network - 10.110.40.10 Forgive me if this i) is impossible, ii) is crazy, iii) the syntax of the command is wrong. I'd rather run it past the list than tinker on production equipment. Thanks for any help and advice, -Stephen- blind leading the blind here but This was recently discussed, and it was pointed out that the decision to encrypt happens before the nat-ing. Correct me if I am wrong, then -- this should work. I should be able to set up a NAT rule that will affect encrypted traffic in the way I want. Someone mentioned to me that this does work in 3.9. Will it work in 3.8? That's what our gear is running. -Stephen- Um no, it wont work. Once the traffic is encrypted you will no longer be able to nat it. The original packet is now and encrypted blob that is the payload of a new packet with a source of your gateway and dest their GW. you can nat the wrapper packet but not the payload. I have 2x ibm x series somethings for fw's, and 2x hp dl360s for vpn servers all running 3.9. Just for clarity, I made this diagram, so we are all talking about the same thing. http://www.openalternatives.com/oa-ipsec.png
Re: pf isakmpd: NAT through encryption interface?
Roy Morris wrote: Stephen Bosch wrote: Dag Richards wrote: Stephen Bosch wrote: Imagine the following scenario: You have two VPN endpoints. One is an OpenBSD system running isakmpd and pf, the other is a VPN concentrator from some vendor. The OpenBSD already has other VPNs set up, all using the same internal network. Renumbering isn't going to work. The VPN concentrator operator has an internal addressing scheme he insists other endpoints conform to. The question, then: Is it even possible to NAT through an encryption interface? For example: OpenBSD internal network: 192.168.45.0/24 Network other guy would prefer OpenBSD use: 10.110.40.0/24 Network other guy is using: 10.110.10.0/24 The command might look like this: nat on $enc_if from 192.168.45.0:network to 10.110.10.0:network - 10.110.40.10 Forgive me if this i) is impossible, ii) is crazy, iii) the syntax of the command is wrong. I'd rather run it past the list than tinker on production equipment. Thanks for any help and advice, -Stephen- blind leading the blind here but This was recently discussed, and it was pointed out that the decision to encrypt happens before the nat-ing. Correct me if I am wrong, then -- this should work. I should be able to set up a NAT rule that will affect encrypted traffic in the way I want. Someone mentioned to me that this does work in 3.9. Will it work in 3.8? That's what our gear is running. -Stephen- Um no, it wont work. Once the traffic is encrypted you will no longer be able to nat it. The original packet is now and encrypted blob that is the payload of a new packet with a source of your gateway and dest their GW. you can nat the wrapper packet but not the payload. I have 2x ibm x series somethings for fw's, and 2x hp dl360s for vpn servers all running 3.9. Yes it does work! I guess I better hold on to these two boxes I have. Seems they are the only ones that do! lol I have A. clients on each end behind a vpn/pf box B. enc0 binat from internal client to public IP of other side client C. /etc/hostname.if alias for the binat IP D. isakmpd.conf uses public IP (A) for phase 1, and (B internal client nat) for phase 2 (ip's changed to protect the innocent. No animals were harmed during this test) Jun 28 13:23:32.881298 (authentic,confidential): SPI 0x84adb14b: 222.222.222.111 111.111.111.111: 222.222.222.222.25247 111.111.111.222.80: S [tcp sum ok] 789729009:789729009(0) win 16384 mss 1460,nop,nop,sackOK,nop,wscale 0,nop,nop,timestamp 345218535 0 (DF) [tos 0x10] (ttl 63, id 29296, len 64) (DF) [tos 0x10] (ttl 63, id 44546, len 84) Jun 28 13:23:32.882822 (authentic,confidential): SPI 0xcf4b18fb: 111.111.111.111 222.222.222.111: 111.111.111.222.80 222.222.222.222.25247: S [tcp sum ok] 3946347346:3946347346(0) ack 789729010 win 16384 mss 1460,nop,nop,sackOK,nop,wscale 0,nop,nop,timestamp 1861954054 345218535 (DF) (ttl 63, id 35574, len 64) (DF) (ttl 64, id 12842, len 84, bad cksum 0!) Jun 28 13:23:32.883716 (authentic,confidential): SPI 0x84adb14b: 222.222.222.111 111.111.111.111: 222.222.222.222.25247 111.111.111.222.80: . [tcp sum ok] ack 1 win 17376 nop,nop,timestamp 345218535 1861954054 (DF) [tos 0x10] (ttl 63, id 31269, len 52) (DF) [tos 0x10] (ttl 63, id 34993, len 72) Jun 28 13:23:37.013444 (authentic,confidential): SPI 0x84adb14b: 222.222.222.111 111.111.111.111: 222.222.222.222.25247 111.111.111.222.80: F [tcp sum ok] 1:1(0) ack 1 win 17376 nop,nop,timestamp 345218543 1861954054 (DF) [tos 0x10] (ttl 63, id 30180, len 52) (DF) [tos 0x10] (ttl 63, id 61997, len 72) Jun 28 13:23:37.013716 (authentic,confidential): SPI 0xcf4b18fb: 111.111.111.111 222.222.222.111: 111.111.111.222.80 222.222.222.222.25247: . [tcp sum ok] ack 2 win 17376 nop,nop,timestamp 1861954062 345218543 (DF) (ttl 63, id 56710, len 52) (DF) (ttl 64, id 21978, len 72, bad cksum 0!) Jun 28 13:23:37.013806 (authentic,confidential): SPI 0xcf4b18fb: 111.111.111.111 222.222.222.111: 111.111.111.222.80 222.222.222.222.25247: F [tcp sum ok] 1:1(0) ack 2 win 17376 nop,nop,timestamp 1861954062 345218543 (DF) (ttl 63, id 40038, len 52) (DF) (ttl 64, id 19310, len 72, bad cksum 0!) Jun 28 13:23:37.014441 (authentic,confidential): SPI 0x84adb14b: 222.222.222.111 111.111.111.111: 222.222.222.222.25247 111.111.111.222.80: . [tcp sum ok] ack 2 win 17375 nop,nop,timestamp 345218543 1861954062 (DF) [tos 0x10] (ttl 63, id 838, len 52) (DF) [tos 0x10] (ttl 63, id 53227, len 72) Jun 28 13:23:38.749637 (authentic,confidential): SPI 0x84adb14b: 222.222.222.111 111.111.111.111: 222.222.222.222.40612 111.111.111.222.80: S [tcp sum ok] 402874189:402874189(0) win 16384 mss 1460,nop,nop,sackOK,nop,wscale 0,nop,nop,timestamp 345218547 0 (DF) [tos 0x10] (ttl 63, id 9220, len 64) (DF) [tos 0x10] (ttl 63, id 51268, len 84) Jun 28 13:23:38.749953 (authentic,confidential): SPI 0xcf4b18fb: 111.111.111.111 222.222.222.111: 111.111.111.222.80 222.222.222.222.40612: S [tcp
Re: pf isakmpd: NAT through encryption interface?
Dag Richards wrote: Um no, it wont work. Once the traffic is encrypted you will no longer be able to nat it. The original packet is now and encrypted blob that is the payload of a new packet with a source of your gateway and dest their GW. you can nat the wrapper packet but not the payload. Just a thought: how about building the tunnel for the nat-ed network only? In this case something along the lines of: ipsec.conf: flow esp from 10.110.40.0/24 to 10.110.10.0/24 peer $remote_gw [...] and pf.conf nat on $int_if from 192.168.45.0/24 to 10.110.10.0/24 - 10.110.40.0/24 source-hash [...] The packet would then have to be reinserted at a point before the encryption decision is made ... I'm not sure if this is possible at all ... if there's a way to redirect the packet to the internal interface again, as if it were just arriving, it should be, though ... krgds /markus
Re: pf isakmpd: NAT through encryption interface?
Hi, Roy: Roy Morris wrote: Yes it does work! I guess I better hold on to these two boxes I have. Seems they are the only ones that do! lol I have A. clients on each end behind a vpn/pf box B. enc0 binat from internal client to public IP of other side client C. /etc/hostname.if alias for the binat IP D. isakmpd.conf uses public IP (A) for phase 1, and (B internal client nat) for phase 2 I've had a closer look at this... In my case, the other peer expects a private IP on my internal network. Your directions involve an alias. Do I need this alias? Can I not just nat on the encryption interface like so? nat on $enc_if from $internal_ip to $remote_internal_ip - $private_nat_address? This is really confusing me. -Stephen-
Re: pf isakmpd: NAT through encryption interface?
Roy Morris wrote: Stephen Bosch wrote: Dag Richards wrote: Um no, it wont work. Once the traffic is encrypted you will no longer be able to nat it. The original packet is now and encrypted blob that is the payload of a new packet with a source of your gateway and dest their GW. you can nat the wrapper packet but not the payload. I have 2x ibm x series somethings for fw's, and 2x hp dl360s for vpn servers all running 3.9. Yes it does work! I guess I better hold on to these two boxes I have. Seems they are the only ones that do! lol I have A. clients on each end behind a vpn/pf box B. enc0 binat from internal client to public IP of other side client C. /etc/hostname.if alias for the binat IP D. isakmpd.conf uses public IP (A) for phase 1, and (B internal client nat) for phase 2 Just to be clear here, I'll try and explain in greater detail. I have a host with IP 10.225.10.10. The remote network is 10.40.10.0/24. The remote network insists that my internal host be on the 10.50.10.0/24 network. In a perfect world, I'd just renumber on my end, or get him to accept my internal network, but he won't do that. So I have to NAT my internal network to a private IP that fits his addressing scheme. I need to NAT 10.225.10.10 so that it will appear as 10.50.10.10 in the remote peer's tunnel. If NAT happens before encryption, then this should be possible. If NAT happens after encryption, I have a problem, and an alias doesn't look like it's going to help. Feedback? -Stephen-
