Gentoo/iptables/ppp0 DNS Issues

switch007 · 12-02-2004, 08:03 AM

PC2 is the gateway, gentoo, with a speedtouch adsl modem (ppp0) and eth0 connected to PC1, windows xp.

PC1 = 192.168.0.1
PC2 = 192.168.0.2

PC1 has gateway set as PC2, i can ping IP's but when i try to ping domain name it times out, ive got no idea what it would be. Is iptables on PC2 blocking dns resolution requests or something?

Help!

Thanks

maxut · 12-02-2004, 08:20 AM

on client side, try to change /etc/resolv.conf like this:
nameserver ISP-DNS-IP-1
nameserver ISP-DNS-IP-2

if it stil fails to resolve domain names, post your iptables script or the output of "iptables -nvL" and "iptables -t nat -nvL"

good luck.

switch007 · 12-02-2004, 08:32 AM

The nameservers are in resolv.conf already, this is the output:

Code:

Chain INPUT (policy ACCEPT 41020 packets, 4795K bytes)
 pkts bytes target     prot opt in     out     source               destination 

Chain FORWARD (policy ACCEPT 112 packets, 16324 bytes)
 pkts bytes target     prot opt in     out     source               destination 

Chain OUTPUT (policy ACCEPT 42699 packets, 7727K bytes)
 pkts bytes target     prot opt in     out     source               destinationp

and

Code:

Chain PREROUTING (policy ACCEPT 468 packets, 30484 bytes)
 pkts bytes target     prot opt in     out     source               destination 

Chain POSTROUTING (policy ACCEPT 50 packets, 3205 bytes)
 pkts bytes target     prot opt in     out     source               destination 
    8   464 MASQUERADE  all  --  *      *       192.168.0.1          0.0.0.0/0  
   18  1186 MASQUERADE  all  --  *      ppp0    0.0.0.0/0            0.0.0.0/0  

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

Thanks

Note: this is a gentoo box with barely anything on it (i installed cron, slocate, openssh, speedtouch, vi, iptables, ipchains)

maxut · 12-02-2004, 08:53 AM

Quote:

Originally posted by switch007

Code:

Chain POSTROUTING (policy ACCEPT 50 packets, 3205 bytes) pkts bytes target prot opt in out source destination 8 464 MASQUERADE all -- * * 192.168.0.1 0.0.0.0/0 18 1186 MASQUERADE all -- * ppp0 0.0.0.0/0 0.0.0.0/0

try followings.

Code:

iptables -t nat -F
iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -o ppp0 -j MASQUERADE

BTW: u dont have a secure firewall. u can make it more secure by using the script generator at www.iptables-script.dk

good luck

switch007 · 12-02-2004, 08:57 AM

That still doesnt work