iptables vs dhcpd
Posted on 2001-07-22
I've set up a NAT firewall for a cable modem. All works perfectly for the two machines behind the wall. To make it easier to take a laptop to other places that use dhcp, I set up dhcpd on the firewall box. Unfortunately, no addresses ever show up at the Win98 laptop.
Watching dhcpd on console (dhcpd -r -f eth1) reveals that the requests never show up.
Something in the firewall script is killing the incoming dhcp requests because if I comment out rc.firewall in rc.local the dhcp works perfectly. I've searched google for other people doing the same thing, but can only find people using ipchains.
Can anyone supply a specific iptables line that would allow incoming dhcp requests only on eth1?
Digging through the iptables man page, the best I make on my own was:
iptables -A udpincoming_packets -p UDP -i eth1 --source-port 67 -j ACCEPT
...since I thought that dhcp requests were upd type on port 67, but that doesn't work.
thanks for any help!