DHCP server configuration

English Network/Internet
#1

Hello,
tried to search for something similar, but i failed, so i’m posting new thread.
Main problem: I can ping my “router” from client PC by IP, but unable to ping anything else on the internet. Firewall is OFF, for testing reasons…
My /etc/dhcpd.conf:

option domain-name "servas";
option domain-name-servers 88.222.0.1, 88.223.0.1;
option routers 192.168.0.1;
option ntp-servers time.nist.gov;
ddns-update-style none;
default-lease-time 14400;
subnet 192.168.0.0 netmask 255.255.248.0 {
  
  default-lease-time 14400;
  max-lease-time 172800;
}
subnet 88.222.152.0 netmask 255.255.248.0 {

  default-lease-time 14400;
  max-lease-time 172800;
}

subnet 192.168.0.0 netmask 255.255.255.0 {
  range 192.168.0.5 192.168.0.80;
  default-lease-time 14400;
  max-lease-time 172800;
}

Internal zone card is configured to have static ip address 192.168.0.1.
Thank you in advance.

#2

You have two overlapping internal subnet declarations and one external subnet (which probably doesn’t belong to you) declaration. That can’t be right.

#3

OK, so i left only this:

option domain-name "servas";
option domain-name-servers 88.222.0.1, 88.223.0.1;
option routers 192.168.0.1;
option ntp-servers time.nist.gov;
ddns-update-style none;
default-lease-time 14400;

subnet 192.168.0.0 netmask 255.255.255.0 {
  range 192.168.0.5 192.168.0.80;
  default-lease-time 14400;
  max-lease-time 172800;
}

But effect is the same - i can only ping “router”-client and client-“router”.

#4

If your client got an IP address and a gateway from the “router” then DHCP is working correctly and being able to ping an external host is a different problem. You can check if the client got a DHCP lease with “ipconfig /all” on Windows and “ifconfig”, “route -n” and “cat /etc/resolv.conf” on Linux.

Sounds like you want IP forwarding. For this you have to configure the router for forwarding and also the firewall rules. There should be a Wiki document on configuring openSUSE as a router. I have a separate gateway/router/firewall so I can’t give you much guidance on configuring openSUSE as a gateway/router.

#5

Yes, i looked at client PC - it has IP from that range, and I believe that is OK. Firewall is OFF, as I mentioned it, so thats why i’m confused - why client cant get to external zone…

#6

Firewall off is not sufficient. The “router” also has to be configured to forward, which is not the default. And in fact if you are NATing the LAN clients, you need the firewall on to do the NAT.

#7

YES! You were right. I configured firewall to enable masquerading, added dhcp server as external client(dont know if that is nessesary), did something else, and it worked!
Thanks for showing the road.