It seems like anything you´ve described. Here is the ruleset : iptables -L -nv Chain INPUT (policy ACCEPT 66 packets, 2754 bytes) pkts bytes target prot opt in out source destination 1332 179K RH-Lokkit-0-50-INPUT all -- * * 0.0.0.0/0 0.0.0.0/0 Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 85 packets, 5151 bytes) pkts bytes target prot opt in out source destination Chain RH-Lokkit-0-50-INPUT (1 references) pkts bytes target prot opt in out source destination 0 0 ACCEPT udp -- * * 80.95.96.7 0.0.0.0/0 udp spt:53 dpts:1025:65535 10 700 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT udp -- * * 192.168.0.11 0.0.0.0/0 udp spt:53 0 0 REJECT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp flags:0x16/0x02 reject-with icmp-port-unreachable 1256 175K REJECT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp reject-with icmp-port-unreachable iptables -L -t nat -nv Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain POSTROUTING (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination As for tutorials - I have read some czech one, I´ll read those from netfilter.org too of course... Thanks in advance, Stanley. -----Original Message----- From: netfilter-admin@xxxxxxxxxxxxxxxxxxx [mailto:netfilter-admin@xxxxxxxxxxxxxxxxxxx] On Behalf Of Antony Stone Sent: Tuesday, March 09, 2004 11:40 AM To: netfilter@xxxxxxxxxxxxxxxxxxx Subject: Re: ping to internet hosts through NameServer of provider On Tuesday 09 March 2004 9:29 am, Stanislav Puffler DiS. wrote: > Hi all, > i´m newbie to fw, have just installed iptables and configured. Have 3 > interfaces, eth0 - internet, eth1 - DMZ (squid, postfix), eth2 - LAN. My > provider has connected my firewall to the Internet via 1 public IP (on > eth0). Internet hosts are resolved via provider´s Name Server (this IP > is in /etc/resolv.conf). If I tried ping to (for example) www.rb.cz > before installing iptables, there was no problem. Now, after installing > iptables, I can´t ping to internet hosts correctly (only on IP - it is > without need of contacting providers NS) - it is working like this : > > [user@machine]$ ping www.rb.cz > IN=eth0 OUT= MAC=.............. SRC="my_providers_nameserver_ip" > DST="ip_on_my_eth0" LEN=127 TOS=0x00 PREC=0x00 TTL=61 ID=3268 DF > PROTO=UDP SPT=53 DPT=32792 LEN=107 So you have a LOGging rule (presumably some time before a DROP rule - not many people LOG ACCEPTed packets), which shows that you are blocking DNS replies from your ISP. Hence you cannot resolve IP addresses. > Ping to resolved IP of www.rb.cz is no problem (ping 193.86.103.40 - > returns a normal replay). Could anyone help me please how to set up > carefully and secure rule to maintain this problem - to permit my > provider´s NS to resolv internet hosts ? Please tell us your ruleset (either the iptables commands you use to set up the rules, or the output of "iptables -L -nv; iptables -L -t nat -nv") and we can suggest what might be wrong. If you are new to networking as well as netfilter, please read one of the excellent tutorials accessible from http://www.netfilter.org and this will help you get a basic setup working. I can recommend Oskar Andreasson's tutorial at http://iptables-tutorial.frozentux.net Regards, Antony. -- Most people are aware that the Universe is big. - Paul Davies, Professor of Theoretical Physics Please reply to the list; please don't CC me.