topic Inter Zone traffic in General Topics

Inter Zone traffic

Ayush_paloalto — Sat, 08 Jun 2019 19:55:49 GMT

I have created a policy rule in palo alto from INSIDE zone to OUTSIDE zone all the traffic is allowed. and I am able to ping from a inside device to a outside host however when I try to ping from outside host to the inside host it is not working.

Do I need to create allow rules from OUTSIDE zone to INSIDE as well?

because in ASA when we intiate the traffic from inside to outside then outside to inside traffic is allowed automatically and we do not need to create rules as the cisco ASA allows traffic by just checking the active session if it were initiated already from the inside zone which has the higher securiy level.

please help me understard this concept in palo alto.

Re: Inter Zone traffic

Chacko42 — Sat, 08 Jun 2019 20:01:24 GMT

@Ayush_paloalto This is called stateful inspection, so the return path for sessions is implicitly allowed.

Furthermore, apps which negotiate random high ports like RPC, FTP, SIP/RTP etc. are automatically detected and implicit rules are in place for these sessions.

So with the zone concept, you allow ping from zone inside to zone outside and that work's fine, as you said.

But your second scenario, ping from zone outside to zone inside is not covered by your rule and so will be matched to the interzone default policy, which per default drops the traffic.

So in short: yes, everything works as expected, return traffic is implicitly allowed and you need an additional rule