Hello,

I am using a Debian Etch box to share the internet conection, recently what's been happening is that none of the computers connected to the server can load a page on the first attempt.

The first time you try to go to a webpage using a URL you get a "Page not found" error, like if the domain didn't exist. Then just refreshing, the page it loads like nothing happened. But if you use IP numbres intead of URLs you can browse the web without problems.

However this doesn't happen if you browing the web from de server, so I'm guessing there is a DNS problem of some sort between the server an the clients.


Conection is shared using the following iptables rules, there is no proxy.

$IPT -P INPUT DROP
$IPT -P OUTPUT ACCEPT
$IPT -P FORWARD ACCEPT
echo 1 > /proc/sys/net/ipv4/ip_forward
$IPT -t nat -A POSTROUTING -o $WAN -j MASQUERADE


All the computers within the network, are configured bia DHCP which has the following configuration

subnet 10.11.12.0 netmask 255.255.255.0 {
range 10.11.12.20 10.11.12.250;
default-lease-time 600;
max-lease-time 7200;
option subnet-mask 255.255.255.0;
option domain-name "xxxxxxx.com";
option domain-name-servers 10.11.12.1;
option broadcast-address 10.11.12.255;
option routers 10.11.12.1;
}


Current contents of resolv.conf

nameserver 208.67.222.222
nameserver 208.67.220.220


I have searched the web and the forums, but i was not quite sure what to search for.

Thanks in advance.

The contents you list for resolve.conf are on your Debian server?
I also gather 10.11.12.1 is the IP address of the Debian server?

If so, the line

tells the clients to use the Debian server for DNS resolution. So you must have a DNS server or DNS cache running on the Debian server. I would guess the problem would be associated with that. If you aren't aware of what might be doing the DNS resolution, look for the process listening on udp/53 (as root):

One other idea did cross my mind, but I don't understand enough about IPv6 to state it coherently. But I know some people have had DNS problems because the browser was configured to try IPv6 before it tried IPv4 (I think).

You pointed me on the right direction.

Indeed i have a DNS server (Bind9), but i had thought it would use the same DNS servers i have in /etc/resolv.conf.

Anyway after looking for the configuration files I found a different pair of dns on /etc/bind/named.conf.options and replaced them with the ones in /etc/resolv.conf.

Everything seems to be working now.

Thanks