Arp issue

[Sanjay_S]

Hi Team,

We have a new requirement as below.

Azure Network Accessing one of the Load Balancer IP.

Consider Azure: 10.0.0.0/24

Firewall Interface eth1: 10.50.0.0/24

Load Balancer: 10.100.0.1

Azure is behind eth1 and Load Balancer is also behind eth1.

So we created a NAT rule as below:

Orginal:

Source: 10.0.0.1(Azure

Destination: 10.50.0.10(Dummy IP in the interface range)

Port: Any

Translated:

Source: 10.50.0.1(Firewall eth1 interface IP)

Destination: 10.100.0.1

Port: Orginal

So user from Azure will try to access the Dummy IP 10.50.0.10 to get to 10.100.0.1.

But when we run the tcpdump we are getting where is 10.50.0.10 and what is the arp, So not sure what is the problem.

We added proxy arp as well to 10.50.0.10 on the firewall. Can you please suggest on this.

[PhoneBoy · Accepted solution]

Proxy ARP does not work in Public Cloud providers.
This is a limitation of these platforms and not specific to Check Point.
You need to configure the appropriate User-Defined Route in Azure to achieve this.