Hello,
I seem to have something broken on my firewall for redirecting incoming
ipip packets to my gateway box. It appears to work fine at times but
fails periodically, typically after a reset/power failure. Usually it
comes back after several reboots of firewall and router but this process
is inconsistent.
The latest reboot had me digging deeper to try to find the real problem
and I have discovered that only the rule in FORWARD chain of the filter
table is firing, not the DNAT in the nat table. I suspect the firewall
is only working when some connection (outgoing ?) wakes up the
masquerade rules but haven't actually found the rule that is active.
The firewall is running on OpenWRT using iptables (old version 1.3.8)
and the rules as I think they should work are
## for
ampr.org tunnels
iptables -t nat -I PREROUTING -p 4 -i eth0.1 -j DNAT \
--to-destination 192.168.99.66
iptables -t filter -I FORWARD -p 4 -i eth0.1 -j ACCEPT
As I understand it, the first re-writes the destination for ipip packets
to my gateway and the second allows them to be forwarded however the
counter on first stays stuck at 0.
A reference to what sounds like a similar problem:
https://sourceforge.net/p/ipcop/mailman/message/17780204/
It would be really nice to get this sorted properly, any debugging hints
appreciated. In particular, am I correct in expecting both rule counters
to match ?
thx ...
... Niall