Dhcp help

i have change my network setup i was using a router but that keep blocking my outside address even if i did use portfording or use the DMZ

so i set the router/modem to bridge mode and setup a PPPOE connection on the linux server and it worked with no problems but…

all my computers on the network did not have any address or ips after that so i want into my webmin and installed the Dhcp server and set it up then all the computer on the network had an local address but did not have a connection to the net

i setup the DNS server to go to which is where the internet Connection is as well as the Dhcp server now im not sure on how to get the internet from the pppoe connection to go to the Eth0 Connection

PPPoe connection is my internet ip (123.2.157.XXX)
Etho is the connection to my local ip (

i am realy new to linux and networking i dont know if i em meant to bridge the connections and how to do that or if their is a better way to do it any help with be grate ty.

When I’m in the situation, I usually just go to Best Buy and pick up a LinkSys router. There’s one that runs Linux right out-of-the box. Costs like $40, and saves me a couple of hours of fiddling. :wink:

But, you probably just need to enable routing on your system. By default, it won’t act as a router. (There’s a checkbox for this in Webmin’s Network Configuration.)

i did what you said about the check box in network configuration is their anything other deals i have to do to get this to work becuse their is still no internet on the other systems and if i can i dont want to buy anything i also did up a small pic on how everything is setup but i am really stuck on this and im still very new to Linux and even this method of networking so any help is grate and i thank you for it.

I’m not sure that a bridge is going to do the trick for you here.

If what you have is a single static IP from your ISP, and you’re running Virtualmin on a Linux box on your internal LAN, then the way to make things work is what you initially tried – using port forwarding.

If port forwarding doesn’t work, we can troubleshoot that aspect of this.

A number of ISP’s block incoming web and email traffic (ports 80, 443, and 25), amongst others, unless the person upgrades to what they consider to be a “business class” line.

So if you aren’t able to connect remotely to your internal systems, it may be due to your ISP’s policies. You may want to ask them if they allow traffic on those ports.

Or it could be a configuration issue that needs to be tweaked.

im finding the problem is not with my isp thay have so far been good service i know thay don’t block any ports but port 25 but that can be unblock by logging into my account and setting that to be unblocked

everyone so far told me thay can connect to my server but me using my out side address eg

when i use my out side address i get sent to my router on port 80 so i change the port on the router to port 8080 but i still get stuck getting past my router using my outside address it come up with fail to connect and with ports open and firewall off and DMZ on

so that why i am try the bridge mode on the router and setup a connection on the Linux server and now i can use my out side address but so then i tried to setup a dhcp server now all the computer on the network get their ip and dhcp server ip and DNS server address and default gateway

but thay just cant get the internet on any computer but the linux server i may not have setup the dhcp server right but how do the uses on the dhcp server get to the pppo connection when thay are useing eth0

I’m not sure, but you might be asking about IP masquerading or NAT, which allows many hosts with private IPs to route through a single system with a public IP (and a private IP).

The basic iptables rule for that looks something like this:

iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

what I understand is first comes: modem -> router -> switch -> computers
I think you want: adslrouter (not giving IP’s) -> linux server (giving IP’s and has 2x ifaces) -> switch -> computers.

1 iface of the linux server is going to the adslrouter, the other iface is going to the switch. All computers must be connected to the switch. Best use CAT 5 cables.

The adslrouter must use DMZ to open the way to your server.