I have an Internet Gateway Device with based Linux System (Linux 2.6.30).

I mad ean automatic script that open many http sessions from many LAN Stations to many Public IP address. And I add capture on the wan interface and on the LAN interface And I found:

  • Some time the NAT keep the private address of the packet when the packet is forwarded to the wan (rarely happened)

  • Some time the NAT does not forward the TCP packet to the wan at all (rarely happened).

The above behaviour are rarely happened. If I launch the test 100 times it happens only 13 times.

Is it a known bug in the NAT of the Kernel? are there some patch to fix this issue?

  • Is it possible you've exceeded the number of connections set in /proc/sys/net/ipv4/netfilter/ip_conntrack_max or /proc/sys/net/netfilter/nf_conntrack_max? – derobert Oct 17 '16 at 15:30
  • Could it be that some packets not properly NATed are from certain TCP connections whose handshake hasn't been successfully completed? Can you dump the packets? – phk Oct 17 '16 at 17:54

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