# Controlling traffic between jails on the same host



## mlager (Mar 29, 2014)

*The Setup:* I've got a pretty simple setup... A FreeBSD 10.0 host with 3 jails on it. The host, and each jail are assigned a public IP address. The host runs PF that controls inbound and outbound traffic for itself and it's jails. All works really nicely. Here's a basic diagram:

HOST: IF: BCE0 - IP: 192.168.1.100
  |
   --- JAIL 1: IF BCE0: IP: 192.168.1.101
   --- JAIL 2: IF BCE0: IP: 192.168.1.102
   --- JAIL 3: IF BCE0: IP: 192.168.1.103

*My Question:* PF does a really good job controlling traffic to and from remote system. I have recently come across the need to limit traffic from jails on the host to other jails on the same host. I.E. HostA-JailA needs to not be able to communicate with HostA-JailB. What I am seeing, however, is that because all these jails share a single interface, the traffic must not be going through PF as it is just seen as local traffic.

I briefly tried to bring up a jail on another interface (lo1 for example) and use NAT to provide it with its connectivity, but even then the local traffic was still not filterable.

There's got to be a way, but my brain hasn't thought of it yet. Any advice would be amazing, thanks so much ahead of time!


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## mlager (Mar 29, 2014)

After spending a bit more time searching through this forum, I found a very helpful thread!

https://forums.freebsd.org/viewtopi...it=block+between+two+IP+addresses+on+same+NIC

I was searching "jails" mostly and when I found this it made me realize it's not really a jail specific question. Anyway, using lo0 in PF to filter the traffic between the jails on the same interface worked great. And I did have "skip lo" in my PF config only because I see it everywhere I look.

Good learning tonight.


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