Packet forwarding between interfaces not working [Solved]

[kiwieater]

Hi there,

I have a weird issue. Consider this simple setup:

+----------------+  MGTNET1  +-------------------+
|                +-----------+                   |
|  Linux Box 01  |           |  OPNsense Box 01  |
|                +-----------+      Site 01      |
+----------------+  SVCNET1  +-------------------+
                              MGT||      SVC||
                              TUN||      TUN||
                                 ||         ||
                                 ||         ||
                                 ||         ||
                                 ||         ||
                                 ||         ||
+----------------+  MGTNET2  +-------------------+
|                +-----------+                   |
|  Linux Box 02  |           |  OPNsense Box 02  |
|                +-----------+      Site 02      |
+----------------+  SVCNET2  +-------------------+

 Symptoms:
    * Linux box 01 can reach OPNsense Box 01 (Ping/SSH/…) on MGTNET1
    * Linux box 01 has a routing table entry to reach MGTNET2 (Gateway: MGTNET1 interface on OPNsense box 01).
    * However, Linux box 01 can't reach Linux Box 02 (Ping/SSH/…)
    * Nevertheless OPNsense box 01 can reach Linux Box 02 (Ping/SSH/…) via MGTTUN (OpenVPN)
    * Ping packets originating from Linux box 01 arrive on MGTNET1 interface of OPNsense Box 01 (TCPdump -i MGTNET1)
    * However, the ICMP/ping packets originating from Linux box 01 are not forwarded to the MGTTUN interface of OPNsense Box 01 (TCPdump -i MGTTUN). In fact, I've checked all the other interfaces on OPNSense Box 1 (unsing TCPdump) to see whether the ICMP/ping packets disappear to somewhere else, but they appear on no other interface at all 
    * Pinging Linux host 2 from Linux host 1 via the SVC* Links works as expected.

Any help/pointer would be greatly appreciated.

Best,
KiwiEater

[kiwieater]

Hi there,

sorry to bother... it was a missing firewall rule.

  Embarrassed...

Best,
KiwiEater