Hello everyone, here is description of my situation: my host is behind NAT server (Linux 2.4.x). By default, INPUT and FORWARD is DROP. OUTPUT is ACCEPT. There are maden some rules that allow to send/receive mail and for PROXY server traffic. Anyway, I want to connect to some server in the external net ( internet). Thatx to command: iptables -A FORWARD -i eth1 -j LOG --log-prefix "IPT:UnhandledForward:" I found in syslog lines like this: Oct 16 19:05:59 slack kernel: IPT:UnhandledForward:IN=eth1 OUT=ppp0 SRC=192.168.1.251 DST=62.111.129.3 LEN=36 TOS=0x00 PREC=0x00 TTL=127 ID=17885 PROTO=UDP SPT=23083 DPT=13073 LEN=16 Oct 16 19:07:44 slack kernel: IPT:UnhandledForward:IN=eth1 OUT=ppp0 SRC=192.168.1.251 DST=62.111.129.3 LEN=36 TOS=0x00 PREC=0x00 TTL=127 ID=18107 PROTO=UDP SPT=23083 DPT=13073 LEN=16 Oct 16 19:10:27 slack kernel: IPT:UnhandledForward:IN=eth1 OUT=ppp0 SRC=192.168.1.251 DST=62.111.129.3 LEN=36 TOS=0x00 PREC=0x00 TTL=127 ID=18888 PROTO=UDP SPT=23083 DPT=13073 LEN=16 Oct 16 19:11:08 slack kernel: IPT:UnhandledForward:IN=eth1 OUT=ppp0 SRC=192.168.1.251 DST=62.111.129.3 LEN=36 TOS=0x00 PREC=0x00 TTL=127 ID=19078 PROTO=UDP SPT=23083 DPT=13073 LEN=16 ...so why in this situation I tryed to just FORWARD ports: SPT=23083 and DPT=13073. Unfortunately it wont work :(. This is what I added: iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A FORWARD -i eth1 -p udp -m multiport --dport 13073,23083 -j ACCEPT Dont know realy why it didnt work( maybe someone can explain me that, because I use similar construction for SMTP and POP3 and it works perfect) Anyway i tryed to make DNAT. I added the following lines: iptables -t nat -A PREROUTING -p tcp -i ppp0 --dport 13073 -j DNAT --to 192.168.1.251:23083 iptables -A FORWARD -p tcp -d 192.168.1.251 --dport 23083 -j ACCEPT iptables -t nat -A PREROUTING -p udp -i ppp0 --dport 13073 -j DNAT --to-destination 192.168.1.251:23083 iptables -A FORWARD -p udp -d 192.168.1.251 --dport 23083 -j ACCEPT ...and this method failed too :( Can anyone give me an hand how to resolve this problem - i will be in debt forever. PS. Please say if any of my description is not understood -- Best regards,
