hello,

I've got an adsl usb-modem web access and I want to share it on my lan...

I've used some iptables rules (copy pasted from the web) to create a 'standard' nat and it looks nice ! any web IP is reacheable from my lan but not the names...

I firstly thought port 53 dns requests will be forward like everything here... but apparently not
Then I tried to use a 'cache' dns server on my nat server but even that, (and even the fact that on debian package, bind is a cache dns server by default) nothing...

I feel like a lost cowboy at the end of my command line, please help.

how does your resolv.conf look?
do you get your ip address from a dhcp server?

and your NAT line looks

iptables -t nat -A POSTROUTING <etc etc> -j MASQUERADE

so (first, nice: you're my fisrt answer on this forum)

resolv.conf server : the dns IPs of my ISP (free.fr)

nameserver 212.27.39.1
nameserver 212.27.39.2

for my IP address, I've something strange since a new card (it's a laptop), it doesn't state automatically, I put it by hand (but no dhcp)
I do only: ifconfig eth0 192.168.0.222 netmask 255.255.255.0 and my local network is ok

and the nat:

iptables -F
iptables -t nat -F
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT

iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS -o ppp0 --clamp-mss-to-pmtu


I repeat that I'm able to ping any web IP from the lan
I probably forget a little stupid detail (as usual)
do you know why dns packets don't go through my nat server (but the others, yes)

thanks for all

should forward udp too for DNS.

sorry for the late... I had a without linux week end

it's working properly now but I don't know why.
I havent' add any rule in my iptables

the problem source was perhaps inside the routing table (I'm not sure because I thought I had done it last time)
each time I boot, after lauching the web connection, I have to do:

route del default (to remove a default line going through 192.168.0.254)
route add default ppp0

and then it's working properly
an other question now: how can I fix it at boot ? (the routes)


I've notice strange things in my configuration... I have a DHCP server on the same machine (only to set gateway and dns) but theses 'client attributes' have been change automatically ?!? from a static IP to a dynamic name.... ISP ? or linux ?