Running DHCP server while port forwarding on linksys router

psychotic · 20th February 2002, 01:50

I have a linksys router, with 2 computer hooked up to it. I have enabled port forwarding to allow people to connect, but when port forwarding is enabled, the DHCP server option (which allows mulitple computers to be connnected) is disabled. Does anyone know another way to get both my computer to connect to the internet while portforwarding is enabled??

FesterHead · 20th February 2002, 18:48

Could you disable the DHCP server and manually assign the second computer an internal lan ip?

I'm not familiar with the Linksys router so not sure if it possible.

Axus · 20th February 2002, 21:34

I have a linksys router and i was wondering how you got around the firewall... could you give me the instructions step by step?

NeoChichiri · 26th February 2002, 14:22

I have a Linksys router hub...and I have DHCP disabled and Port forwarding enabled...and I have anywhere between 2-4 computers all on at the same time.

If you're using port forwarding make sure that you are NOT forwarding ALL ports to the server computer...otherwise you will have problems connecting from the other computers. You should only tell the hub to forward specific ports or port ranges to forward to the computer...and make sure that those ports aren't required for specific services on the computers.

26th February 2002, 18:24

Here is a a good page:
LinkSys Port Forwarding

psychotic · 26th February 2002, 22:59

I have 2 computers with port 8000 and 8001 forwarded to one computer. They can both connect to eachother at the same time, but only one can connect to the internet at a time while the DHCP server is turned off. I know people have told me to assign static IP address to each of my computer using the router, but will this let both computers access the internet? Does anyone with a linksys router know how to do this??

Technocrat6400 · 27th February 2002, 03:07

This is a repost of my previous post about configuring a Linksys router for SHOUTCast...

First, we have to make some changes to our network setup. We can't use DHCP and forward ports at the same time, so we'll have to assign IP addresses to all the computers on our network.

To begin, we need some info from the router. We'll log into the web-based interface for our router. The default address is 192.168.1.1. Enter your password and click the "Status" tab. Now make note of your listed DNS servers under the WAN Section. These will be important in getting our computers behind the router to connect to the Internet once we assign IPs to them.

Next, click the "DHCP" tab. Here we need to ensure that DHCP server is set to "Disable". Click the radio button next to "Disable" and click "Apply". This is will ensure that our port forwarding works.

Now to assign IP addresses on most Windows boxes goto Control Panel and open Network Properties or Network and Dial-up Connections. Here we'll see a listing of network components. The one we're interested in in is the one called "TCP/IP -> <network card>" where <network card> is the network card connected to the router (usually the only network card in the system). Double-click this entry.

Various versions of Windows look quite different here. First you want to find the option for "Specify and IP Address" and turn that on. That will activate several fields for IP Address, Subnet Mask, and Default Gateway. The Subnet Mask should be 255.255.255.0 in most cases. Default Gateway should be the address of your router on our LAN, 192.168.1.1 by default. The IP Address should be 192.168.1.x where x is a different number for each computer on our network. We'll assign 192.168.1.2 to the computer running SHOUTCast server.

Now we need to setup our DNS server addresses. These are the computers that translate the domain names humans use into the IP addresses that computers use. In Windows 2000 these settings will be directly below where you set you IP address. In most other verisons you'll find them on the "DNS" tab. Make sure that "Enable DNS" is checked and fill in the address we got from the router earlier in the space provided. When we have the first one entered we'll click "Add" and repeat the process for the second and, if it exists, the third. In Windows 2000 we'll just have two boxes to fill in and no "Add" button.

Now we click "Ok" and close Networking Properties and restart Windows.

Next we have to log into the web-based interface for our router again to set up the port forwarding.

Click the "Advanced" tab and then click the "Forwarding" tab. We'll see a series of rows with two fields seperated by "To" labled "Ext. Port", a drop box with entries for TCP, UDP, and Both, and a place for an IP address. If you have a later firmware on your router you may have check-boxes for TCP and UDP, a filed labled "Customized Applications", and a check-box labled "Enable".

We want to set the "Ext. Port" range to the ports our SHOUTCast server will be working on. If we left the port assignments in the server config at their defaults these will be 8000 for connections and 8001 for the source stream, so we'll enter "8000" in the first port field and "8001" in the second port field. We will enable both TCP and UDP. In the case of the earlier firmware just select "Both" from the drop box. With the later firmware check both the TCP and UDP check-boxes. For IP Address we want to enter the IP address of the computer our SHOUTCast server is running on, 192.168.1.2 if you were following the directions above. If you have the newer firmware be sure to check "Enable" and you don't have to worry about "Customized Applications" Click apply and you're done!

Alternativly, instead of setting port forwarding you clould just put your SHOUTCast server in the DMZ. This is less secure as it exposes all ports on the machine. To do this, click the "Advanced" tab in the router config and then click "DMZ Host". In the space provided enter the IP address of the SHOUTCast server, 192.168.1.2 in the previous example, and click apply.

Hope this helps out.

Technocrat6400

psychotic · 27th February 2002, 03:55

You are my saviour, i give you this.... !@#!@@@!!!@#@, jiberish... it may not seem like much but it is all i can think of offering. THANKS!

Technocrat6400 · 27th February 2002, 15:37

Hehe, you're welcome, dude.

Let me know how it works out.

Technocrat6400

buddhahat · 27th February 2002, 22:51

weird. on my linsys 4 port router I
have no problem with having both
DHCP and port forwarding working
together. Of course I'm not trying to
port forward on machines that use
DHCP. I have a mix of static and dynamically
allocated IPs on my network.

hmmm

Shirow · 27th February 2002, 23:22

I have DHCP enabled on my d-link and port forward. It's not a problem per se, unless one of the IP's changes on one of the machines. Since I (hardly ever) reboot my Shoutcast machine, it's not really a problem. I only leave DHCP enabled out of laziness though.

Technocrat6400 · 28th February 2002, 01:01

DHCP and port forwarding can co-exist on the same router. You just have to make sure that the IP address of the machine the ports are forwarded to doesn't change.

Another problem is that sometimes the router's DHCP server won't properly recognize what IPs were manually set and try to hand those out to a DHCP machine. This can usually be fixed by upgrading your router to the latest firmware.

All in all, if you're a networking novice, it's best just to assign IPs to all your machines and leave DHCP disabled.

Technocrat6400

20th February 2002, 01:50	#1
psychotic Junior Member Join Date: Oct 2001 Posts: 28	Running DHCP server while port forwarding on linksys router I have a linksys router, with 2 computer hooked up to it. I have enabled port forwarding to allow people to connect, but when port forwarding is enabled, the DHCP server option (which allows mulitple computers to be connnected) is disabled. Does anyone know another way to get both my computer to connect to the internet while portforwarding is enabled??

27th February 2002, 03:07	#7
Technocrat6400 Junior Member Join Date: Feb 2002 Posts: 7	SHOUTCasting through a Linksys Cable/DSL Router for Dummies This is a repost of my previous post about configuring a Linksys router for SHOUTCast... First, we have to make some changes to our network setup. We can't use DHCP and forward ports at the same time, so we'll have to assign IP addresses to all the computers on our network. To begin, we need some info from the router. We'll log into the web-based interface for our router. The default address is 192.168.1.1. Enter your password and click the "Status" tab. Now make note of your listed DNS servers under the WAN Section. These will be important in getting our computers behind the router to connect to the Internet once we assign IPs to them. Next, click the "DHCP" tab. Here we need to ensure that DHCP server is set to "Disable". Click the radio button next to "Disable" and click "Apply". This is will ensure that our port forwarding works. Now to assign IP addresses on most Windows boxes goto Control Panel and open Network Properties or Network and Dial-up Connections. Here we'll see a listing of network components. The one we're interested in in is the one called "TCP/IP -> <network card>" where <network card> is the network card connected to the router (usually the only network card in the system). Double-click this entry. Various versions of Windows look quite different here. First you want to find the option for "Specify and IP Address" and turn that on. That will activate several fields for IP Address, Subnet Mask, and Default Gateway. The Subnet Mask should be 255.255.255.0 in most cases. Default Gateway should be the address of your router on our LAN, 192.168.1.1 by default. The IP Address should be 192.168.1.x where x is a different number for each computer on our network. We'll assign 192.168.1.2 to the computer running SHOUTCast server. Now we need to setup our DNS server addresses. These are the computers that translate the domain names humans use into the IP addresses that computers use. In Windows 2000 these settings will be directly below where you set you IP address. In most other verisons you'll find them on the "DNS" tab. Make sure that "Enable DNS" is checked and fill in the address we got from the router earlier in the space provided. When we have the first one entered we'll click "Add" and repeat the process for the second and, if it exists, the third. In Windows 2000 we'll just have two boxes to fill in and no "Add" button. Now we click "Ok" and close Networking Properties and restart Windows. Next we have to log into the web-based interface for our router again to set up the port forwarding. Click the "Advanced" tab and then click the "Forwarding" tab. We'll see a series of rows with two fields seperated by "To" labled "Ext. Port", a drop box with entries for TCP, UDP, and Both, and a place for an IP address. If you have a later firmware on your router you may have check-boxes for TCP and UDP, a filed labled "Customized Applications", and a check-box labled "Enable". We want to set the "Ext. Port" range to the ports our SHOUTCast server will be working on. If we left the port assignments in the server config at their defaults these will be 8000 for connections and 8001 for the source stream, so we'll enter "8000" in the first port field and "8001" in the second port field. We will enable both TCP and UDP. In the case of the earlier firmware just select "Both" from the drop box. With the later firmware check both the TCP and UDP check-boxes. For IP Address we want to enter the IP address of the computer our SHOUTCast server is running on, 192.168.1.2 if you were following the directions above. If you have the newer firmware be sure to check "Enable" and you don't have to worry about "Customized Applications" Click apply and you're done! Alternativly, instead of setting port forwarding you clould just put your SHOUTCast server in the DMZ. This is less secure as it exposes all ports on the machine. To do this, click the "Advanced" tab in the router config and then click "DMZ Host". In the space provided enter the IP address of the SHOUTCast server, 192.168.1.2 in the previous example, and click apply. Hope this helps out. Technocrat6400

27th February 2002, 22:51	#10
buddhahat Junior Member Join Date: Feb 2002 Posts: 4	linksys and port forwarding weird. on my linsys 4 port router I have no problem with having both DHCP and port forwarding working together. Of course I'm not trying to port forward on machines that use DHCP. I have a mix of static and dynamically allocated IPs on my network. hmmm

28th February 2002, 01:01	#12
Technocrat6400 Junior Member Join Date: Feb 2002 Posts: 7	buddhahat and Shirow are right... DHCP and port forwarding can co-exist on the same router. You just have to make sure that the IP address of the machine the ports are forwarded to doesn't change. Another problem is that sometimes the router's DHCP server won't properly recognize what IPs were manually set and try to hand those out to a DHCP machine. This can usually be fixed by upgrading your router to the latest firmware. All in all, if you're a networking novice, it's best just to assign IPs to all your machines and leave DHCP disabled. Technocrat6400

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20th February 2002, 18:48	#2
FesterHead Alumni Join Date: Sep 2001 Location: Maui, Hawaii Posts: 14,109	Could you disable the DHCP server and manually assign the second computer an internal lan ip? I'm not familiar with the Linksys router so not sure if it possible.

20th February 2002, 21:34	#3
Axus Junior Member Join Date: Feb 2002 Posts: 4	I have a linksys router and i was wondering how you got around the firewall... could you give me the instructions step by step?

26th February 2002, 14:22	#4
NeoChichiri Junior Member Join Date: Feb 2002 Posts: 2	I have a Linksys router hub...and I have DHCP disabled and Port forwarding enabled...and I have anywhere between 2-4 computers all on at the same time. If you're using port forwarding make sure that you are NOT forwarding ALL ports to the server computer...otherwise you will have problems connecting from the other computers. You should only tell the hub to forward specific ports or port ranges to forward to the computer...and make sure that those ports aren't required for specific services on the computers.

26th February 2002, 18:24	#5
Sawg Guest Posts: n/a	Here is a a good page: LinkSys Port Forwarding

26th February 2002, 22:59	#6
psychotic Junior Member Join Date: Oct 2001 Posts: 28	I have 2 computers with port 8000 and 8001 forwarded to one computer. They can both connect to eachother at the same time, but only one can connect to the internet at a time while the DHCP server is turned off. I know people have told me to assign static IP address to each of my computer using the router, but will this let both computers access the internet? Does anyone with a linksys router know how to do this??

27th February 2002, 03:55	#8
psychotic Junior Member Join Date: Oct 2001 Posts: 28	You are my saviour, i give you this.... !@#!@@@!!!@#@, jiberish... it may not seem like much but it is all i can think of offering. THANKS!

27th February 2002, 15:37	#9
Technocrat6400 Junior Member Join Date: Feb 2002 Posts: 7	Hehe, you're welcome, dude. Let me know how it works out. Technocrat6400

27th February 2002, 23:22	#11
Shirow Major Dude Join Date: Dec 2000 Posts: 604	I have DHCP enabled on my d-link and port forward. It's not a problem per se, unless one of the IP's changes on one of the machines. Since I (hardly ever) reboot my Shoutcast machine, it's not really a problem. I only leave DHCP enabled out of laziness though.