IPSEC VPN ECMP - Issue

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IPSEC VPN ECMP - Issue

Dear Collegues,

 

Let imagine the following situation:

 

PA Firewall connected to two ISP, e1/1 - 1.1.1.1 and e1/4 - 2.2.2.2.

Default virtual router with ECMP configured with weights e1/1-50 and e1/4-50.

 

IPSEC tunnel configured to the remote site, IKE Gateway configured on interface e1/4.

 

Tunnel is green, everything seems to be fine... but:

I see around 50% packets lost.

During troubleshooting I see that half of the ESP packets goes via e1/1 and other half via e1/4.

Pacekts which goes via e1/1 has IP address of e1/4 (2.2.2.2) and are lost.

 

I assume that I could use a PBF to resolve this issue, am I right?

 

Best,

Przemek

1 accepted solution

Accepted Solutions

Hi,

 

Traffic generated on the firewall, like in this case doesn't work with the PBR.

I fiexed the problem by configuring two Virtual Routers - each one for a provider.

Then instead of ECMP I configured a load sharing with redundancy (for internet traffic, not for the vpn tunnels).

 

Best,

Przemek.

View solution in original post

4 REPLIES 4

Cyber Elite
Cyber Elite

Yup,

PBF is going to be the best way to actually resolve this. I imagine that the remote site has a static IP?

Unfortunaltely not, and it seems that I have the same issue with GlobalProtect.

 

I have one tunnel with static IP, and I did a workeranoud - putted static route to this particular IP.

In case of other tunnels, I putted also static routes as a temporary solution.

But of course it's not what I want to have.

 

Any ideas how to exactply configure PBR?

 

I tried with:

Zone Internet, Source IP 2.2.2.2 forwarded to e1/4 - but it doesn't work....

 

Cheers,

Przemek

Drawing1.png

 

I enclosed a drawing to make it more clear.

On IKE GW local interface is configured to e1/4 - so all IKE1 traffic goes well (green line).

Unfortunately ESP packets are load balanced and goes via e1/1 and e1/4 (orange lines).

 

What I have to do is to force PA to send ESP packets via e1/4 interface.

ESP packets always have correct IP source address (2.2.2.2) only issue is that half of it goes via e1/1 interface.

 

Thank you in advance for your help.

 

Cheers,

Przemek

Hi,

 

Traffic generated on the firewall, like in this case doesn't work with the PBR.

I fiexed the problem by configuring two Virtual Routers - each one for a provider.

Then instead of ECMP I configured a load sharing with redundancy (for internet traffic, not for the vpn tunnels).

 

Best,

Przemek.

  • 1 accepted solution
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