Complex NAT problems

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Title: Complex NAT problems

Hi

I have a strage problem with iptables NAT

I try to join 2 net with the same ip.


fwinet-2:~# iptables -L -n -t nat -v
Chain PREROUTING (policy ACCEPT 41232 packets, 2376K bytes)
 pkts bytes target     prot opt in     out     source               destination
   94  4743 NETMAP     all  --  eth2   *       172.0.0.0/8          172.20.4.0/24       172.16.4.0/24
    7   420 NETMAP     all  --  eth1   *       172.16.4.0/24        172.20.3.0/24       172.16.33.0/24

Chain POSTROUTING (policy ACCEPT 21845 packets, 1167K bytes)
 pkts bytes target     prot opt in     out     source               destination
    0     0 NETMAP     all  --  *      eth1    172.16.33.0/24       172.16.4.0/24       172.20.3.0/24
  654 33367 NETMAP     all  --  *      eth2    172.16.4.0/24        172.0.0.0/8         172.20.4.0/24
    0     0 SNAT       all  --  *      eth0    172.16.0.0/16        0.0.0.0/0           to:192.168.8.6
    0     0 SNAT       all  --  *      eth0    172.40.40.0/22       0.0.0.0/0           to:192.168.8.6
    0     0 SNAT       all  --  *      eth0    172.60.60.0/24       0.0.0.0/0           to:192.168.8.6
  394 32515 SNAT       all  --  *      eth0    10.152.24.100        0.0.0.0/0           to:192.168.8.6
    0     0 MASQUERADE  all  --  *      eth1    0.0.0.0/0            172.16.4.14

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination


The 1º rule in POSTROUTING table don´t work, the packets go to the inteface eth1 with the original ip, i have the same problem for the other NETMAP rules(i also try with SNAT/DNAT) but when y reboot de firewall the rules apply correctly.

This only happend when modify the rules and no reboot, if reboot and load the firewall script (with the new rules) all work ok.


fwinet-2:~# tcpdump -i eth2 -n icmp
tcpdump: listening on eth2
13:25:38.157106 172.16.33.1 > 172.20.4.11: icmp: echo request
13:25:39.158705 172.16.33.1 > 172.20.4.11: icmp: echo request

fwinet-2:~# tcpdump -i eth1 -n icmp
tcpdump: listening on eth1
13:25:43.163094 172.16.33.1 > 172.16.4.11: icmp: echo request

It´s very strange.

fwinet-2:~# uname -a
Linux fwinet-2 2.4.26 #2 Mon May 17 21:11:05 CEST 2004 i686 unknown


gretings

David Cardeñosa


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