Hi, I have a Linux box with two interfaces, eth0 and eth1. eth1 is a wireless interface with connects to a network and receives a DHCP address. eth0 connects to a AP (with a cross over cable) and provides Internet connection to a bunch of clients. The setup looks like this AP1 <--> eth0 eth1 <---> AP2<---> DHCP server. Using brctl I create a bridge with eth1 and eth0. I have not assigned an IP address for the bridge. eth1 receives an IP address for the DHCP server. When a client connects to AP1 and it requests an IP address from the same DHCP server, I am not able to see the request on the DHCP server. I did a tcpdump on eth0, eth1 and br0. I am able to see the DHCP request packet with the client MAC address on all three interfaces. But for some reason, the DHCP request is not forwarded to the DHCP server. > I suggest that you bridge eth0 and eth1 together and then DHCP the bridge interface. > I don't think that this will have any thing to do with it, but make sure that ip_forward is not interfering with any thing. > Also what, if any thing, do you have for an IPTables config? I cannot perform DHCP for the bridge for the DHCP server tracks each interface that is assigned an IP and this setup is designed to make it transparent to the DHCP server. I have set ip_forward to be 1. (/proc/sys/net/ipv4/ip_forward) It makes no difference if it is 1 or 0. iptables is empty and the default policy is to accept for all three chains. $ brctl show br0 br0 8000.001641162.ba no eth0 eth1 ebtables -A FORWARD -d Broadcast --log-level info -j ACCEPT ebtables -t broute -A BROUTING -p ARP -arp-dst-mac $ETH1_MAC --log-level info -j DROP // drop ARP packets destined for eth1 and do not fwd it to eth0 ebtables -t broute -A BROUTING -d Broadcast -i eth0 --log-level info -j ACCEPT // all broadcast packets must be fwded. $tail -f /var/log/messages <extract> kernel: IN=eth0 OUT= MAC source <newclient> MAC dest FF:FF:FF:FF:FF:FF proto 0x0800 IP proto 17 SPT 68 DST 67 kernel: IN=eth0 OUT= eth1 MAC source <newclient> MAC dest FF:FF:FF:FF:FF:FF proto 0x0800 IP proto 17 SPT 68 DST 67 I did a tcpdump on eth1 (wireless interface) and eth0 (wired interface) and both show the DHCP packet. But this DHCP packet is not forwarded to the DHCP server via eth1 $netstat -rn 116.69.66.0 0.0.0.0 255.255.255.0 U 0 0 eth1 0.0.0.0 116.69.66.0 0.0.0.0 UG 0 0 eth1 I see that there is a route to the external world through eth1. I can ping google.com and the rest of the world through eth1. But I cannot forward traffic received from eth0 to the external world. Any help is greatly appreciated. I thank you for your patience in reading this entire message. Thanks Regards Knight -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
