Folks,
Try as I might, I am missing something as far as getting port
forwarding to work. I have tried this on RH 9, and now on
Slackware 9, and get the same results.
I have a regular script that works on another machine, but
even the simplest trial does not work:
root@gw:~# echo 1 > /proc/sys/net/ipv4/ip_forward
root@gw:~# iptables -t nat -A POSTROUTING -d ! 10.1.1.0/24 \
-j MASQUERADE
root@gw:~# iptables -t nat -A PREROUTING -p tcp -i eth0 \
-d 66.153.4.7 --dport 143 -j DNAT --to 10.1.1.6:143
root@gw:~# iptables -A FORWARD -p tcp -i eth0 -d 10.1.1.6 \
--dport 143 -j ACCEPT
iptables -n -L -v shows traffic on the imap port:
root@gw:~# iptables -n -L -v
Chain INPUT (policy ACCEPT 582 packets, 40585 bytes)
pkts bytes target prot opt in out source
destination
Chain FORWARD (policy ACCEPT 3 packets, 222 bytes)
pkts bytes target prot opt in out source
destination
3 144 ACCEPT tcp -- eth0 * 0.0.0.0/0 10.1.1.6
tcp dpt:143
Chain OUTPUT (policy ACCEPT 3145 packets, 254K bytes)
pkts bytes target prot opt in out source
destination
root@gw:~# iptables -n -L -v -t nat
Chain PREROUTING (policy ACCEPT 1838 packets, 133K bytes)
pkts bytes target prot opt in out source
destination
1 48 DNAT tcp -- eth0 * 0.0.0.0/0
66.153.4.7 tcp dpt:143 to:10.1.1.6:143
Chain POSTROUTING (policy ACCEPT 22 packets, 1292 bytes)
pkts bytes target prot opt in out source
destination
Chain OUTPUT (policy ACCEPT 4 packets, 269 bytes)
pkts bytes target prot opt in out source
destination
But I always get:
Could not open connection to the host, on port 143: Connect failed
The following modules are loaded:
root@gw:~# lsmod
Module Size Used by Tainted: P
ipt_state 536 0 (autoclean)
ipt_MASQUERADE 1272 0
iptable_nat 14904 1 [ipt_MASQUERADE]
ip_conntrack 18016 2 [ipt_state ipt_MASQUERADE iptable_nat]
iptable_filter 1644 1 (autoclean)
ip_tables 11768 6 [ipt_state ipt_MASQUERADE iptable_nat
iptable_filter]
I think that the forwarding part is working, because I set up another
PC on the internal LAN to use this box as the default router, and am
able to reach the Internet through it.
Is there another step I'm missing? Help, please!
Thanks in advance!
PK
