In RHEL 6.1, I'm running 3x VMs and 2x virtual switches as per the following simplified description:
- firewall -> eth0: sw-backend and eth1: sw-dmz
- be-vm -> eth0: sw-backend - default gw is the firewall VM
- dmz-vm -> eth0: sw-dmz - default gw is the firewall VM
The firewall VM has a rule allowing be-vm to SSH to dmz-vm. I can ping from be-vm to dmz-vm and even establish connections, but no data seems to pass through. i.e:
be-vm# telnet dmz-vm 22 Trying dmz-vm... Connected to dmz-vm (x.x.x.x) Escape character is '^]'.
... and that's as far as it gets.
The reason for the title mentioning changes between RHEL5 and RHEL6 is that these exact VMs and networks set-up work fine in RHEL 5.7.