Site-to-Site VPN from a Palo Alto Firewall in the AWS.

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L2 Linker

Site-to-Site VPN from a Palo Alto Firewall in the AWS.

Folks,

We have provisioned a Palo Alto Firewall in one of the AWS VPC. This is essentially a single legged deployment and the function of this firewall will only be to act as a transit firewall.

 

This firewall will have VPN connectivity to the corporate firewall and to some other remote VPC's. Traffic filtering will be done on this Palo Alto Firewall.

 

The issue we are facing is that we do not see any VPN getting negotiated from this Palo Alto Firewall to either the remote VPC or to the corporate firewall. The Palo Alto firewall has a RFC1918 IP address on it's Eth1/1 interface and then this IP address has been allocated a Elastic IP on the AWS console. At present we are going step-by-step and looking at the errors on the Phase-1 IKE connections.

 

Our corporate firewall which is a Juniper does get the Phase-1 messages from this Palo Alto firewall but throws out an error saying "Rejected an IKE packet on ethernetx/y from a.b.c.d:500 to e.f.g.h:500 with cookies ********* and 00000000 because an initial Phase 1 packet arrived from an unrecognized peer gateway.

 

a.b.c.d is the Elastic IP provided in AWS

e.f.g.h is the Public interface IP of the Juniper firewall.

 

Could someone throw some light on what could be the issue? Is there some way to work on this?

 

 

Thanks!!!

 

L5 Sessionator

Re: Site-to-Site VPN from a Palo Alto Firewall in the AWS.

I'm not sure about Junipers but on our devices when you see "00000000" in the log for your peer that means it doesn't recognize it or have a way to route back to it. It amost looks as if something is NAT'ing out for your firewalls untrust interface. Can you ensure that your PAN firewalls Untrust interface is reachable via internet? easiest way to do that would be to add a management profile to your Untrust interface for ping. If you can successfully do this be sure you have provided the correct IP addresses. 

 

Palo Alto Networks Guru

Re: Site-to-Site VPN from a Palo Alto Firewall in the AWS.

Also, make sure the Juniper isn't configured for peer identification based on the IP address of the VM-Series because the VM-Series is configured with a private IP on the firewall but the packets arrive on the Juniper with a source IP of the IEP.  When those don't match, peer identification fails.  Instead, use something like FQDN or and email address as the peer identificaiton.

L2 Linker

Re: Site-to-Site VPN from a Palo Alto Firewall in the AWS.

Thanks, in this case the Juniper also behaves the same. That is why for some reason I believe the ID that the PAN is taking to the Juniper may be incorrect.

 

Yes, the PAN interface is reachable over the Internet using the EIP assigned by AWS.

We can ping/HTTPS to the EIP using the allowed IP range.

 

Do you know if the EIP assigned on the AWS needs some different setting? I mean some NAT policy or something?

 

Thanks for the response and suggestions on this.

L2 Linker

Re: Site-to-Site VPN from a Palo Alto Firewall in the AWS.

We did not specifically configured the Juniper for any peer identification. The logs shows that the assinged EIP is reaching the Juniper so that should be correct.

 

The other challenge here is we would need to build VPN tunnels from this PAN to other VPC's as well so all configuration would need to reside on the PAN itself.

 

We did try by adding peer ID/local ID on the PAN but nothing seems to work. :-(

L5 Sessionator

Re: Site-to-Site VPN from a Palo Alto Firewall in the AWS.

what type of error does the IKEMGR log show on the PAN firewall? you can see that by running 

less mp-log ikemgr.log or something of that effect. 

Also out of curiosity check the ENI that is used for the VPN termination point on the VM series and see if Source Destination checks is turned on. If so as a test turn that off. 

L2 Linker

Re: Site-to-Site VPN from a Palo Alto Firewall in the AWS.

It just shows failed due to timeout

 

 ====> PHASE-1 NEGOTIATION STARTED AS INITIATOR, MAIN MODE <====
                                                      ====> Initiated SA: a.b.c.d[500]-1.1.1.1[500] cookie:916a1f78c71fbe00:0000000000000000 <====

 

Failed SA: a.b.c.d[500]-1.1.1.1[500] cookie:916a1f78c71fbe00:0000000000000000 <==== Due to timeout.
2018-01-23 22:02:17.000 -0800  [INFO]: {    4:     }: ====> PHASE-1 SA DELETED <====

 

 

Here the a.b.c.d is the private IP of the PAN Untrust interface and 1.1.1.1(changed) is the Juniper end IP.

 

 

The Source/Destination checks have been turned off as per the guidance from the documents.

L5 Sessionator

Re: Site-to-Site VPN from a Palo Alto Firewall in the AWS.

We should never see the private IP address is Phase 1 as this is where the peers are authenticated. If the Juniper doesn't have a routable public IP address then you need to be in aggressive mode on the PAN VM-Series for your VPN setup. At this point I wouldn't deem this an issue with VM series firewall itself. My suggestions here are

 

1. Figure out why your Juniper Private IP is being sent to the PAN VM-Series firewall

2. If the Juniper doesn't have a static IP address then configure the VM-Series in Aggressive Mode. 

L2 Linker

Re: Site-to-Site VPN from a Palo Alto Firewall in the AWS.

The above log I took was from the PAN device. This is the one which is showing the Private IP.

The PAN is the initiator and it starts the VPN tunnel with it's private IP.

 

Now, technically this IP should be NATTted by the AWS and the EIP should be forwarded to the Juniper.

The Juniper does show the EIP in it's logs. :)

 

Is there a way to configure the PAN to send the EIP itself in the logs it sends to the Juniper?

L5 Sessionator

Re: Site-to-Site VPN from a Palo Alto Firewall in the AWS.

I misunderstood the private IP being from the PAN so that log is correct. If the public IP addresses are correct then it may go back to what Warby said in the previous post about an identifier. You may need to try a peer identifier. This link is just to illustrate the peer identifier setup.
https://live.paloaltonetworks.com/t5/Configuration-Articles/IPSec-VPN-Tunnel-with-Peer-Having-Dynami...
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