ECMP + 3 Internet links + Outgoing traffic

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L3 Networker

ECMP + 3 Internet links + Outgoing traffic

Hello friends!

 

We have now 3 ISPs, we started to use load balancing (all methoeds tested);

ScreenShot293.jpg

 

Problem: Sometimes, packets from PA220, interface 1/4 (ISP 1),  goes out to internet thru interface 1/5 (ISP 2).

User's traffic with no problem.. But PA220 internet traffic (VPN establishment for example) is inconsistent.

ScreenShot294.jpg

 

 

PA220 VPN initial IKE traffic example

VPN Gateway A

PA220 IP a.a.a.a (int 1/4)  >>> peer IP b.b.b.b

 

At monitor > traffic we see

IP a.a.a.a (int 1/4) going thru int 1/5

VPN doesnt establish

 

Scenario as per below:

"VR-LAN" for LAN (lan interface + tunnel intrefaces)

"VR-WAN" for Internet links (all default routes with same cost)

 

 

Is there a way to internet traffic from PA220 be out of that load balacing ?

L6 Presenter

Re: ECMP + 3 Internet links + Outgoing traffic

Your diagram has 2 firewalls but you're referencing specific interfaces in different firewalls.  Can you explain a bit more how it's cabled up?

L3 Networker

Re: ECMP + 3 Internet links + Outgoing traffic

Hello.... we have 2 in HA... we deal with just 1... the active one...

L2 Linker

Re: ECMP + 3 Internet links + Outgoing traffic

Just setup a static route to the public IP on the endpoint for the VPN, via 1 of the 3 interfaces.

This way the VPN wil always go out via this specific route instead of randomly (as dictated via ECMP)

For redundancy you could setup multiple tunnels and have routing figure out the best path, but that would only work when the other side has a PaloAlto as well (or a Juniper SRX/SSG).

 

Highlighted
L3 Networker

Re: ECMP + 3 Internet links + Outgoing traffic

hello thanks for the reply... but the VPN doesnt establish very well..... because of the worng behavior at public interface... 

INT 1/4 public IP is 200.200.200.2... gateway is 200.200.200.1

But that traffic from 1/4 (200.200.200.2) is going thru 1/5.... (NATed to 1/5 IP) and then VPN doesnt establish (the other side expect 200.200.200.2.... )

 

that is the main problem... 

L2 Linker

Re: ECMP + 3 Internet links + Outgoing traffic

Hi,

 

I think you missed my point.

You have 3 equal cost paths, making the FW semi-randomly choosing the path to the VPN endpoint Public IP.

By entering a single new route, just for the Public IP of the VPN Endpoint, to go out over only 1 of the interfaces, then you would have a consistend outgoing public IP. And when the return traffic comes in, it would follow the same route in reverse

 

Regards

Florian

 

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