Accessdabbler
Technical User
How does a computer gets its IP settings by DHCP if the DHCP server is on the far side of a router (or can it)?
Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations Chriss Miller on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
DHCP question 2
- Thread starter Accessdabbler
- Start date
- Status
-
2
- #2
- Thread starter
- #3
Accessdabbler
Technical User
OK, so if the router is not configured to forward broadcasts and has not been setup for DHCP, I assume the DHCP will fail?
I guess I'm asking so that I understand the importance of putting certain servers/services on the "near" side of a router.
I guess I'm asking so that I understand the importance of putting certain servers/services on the "near" side of a router.
GrnEyedLdy
Instructor
Accessdabbler,
If your Router is not RFC1542 compliant, (cannot pass DHCP discover packets), you can configure a DHCP relay agent on the side of the router that does not have a DHCP server on it.
The DHCP relay agent listens for DHCP discover packets and forwards them across the router to the DHCP server.
Hope this helps,
Patty![[ponytails2]](/data/assets/smilies/ponytails2.gif "[ponytails2] [ponytails2]")
If your Router is not RFC1542 compliant, (cannot pass DHCP discover packets), you can configure a DHCP relay agent on the side of the router that does not have a DHCP server on it.
The DHCP relay agent listens for DHCP discover packets and forwards them across the router to the DHCP server.
Hope this helps,
Patty
Be more descriptive what are you trying to do ! set up a DMZ or something ?
You could have a router for a dmz running dhcp on an external network and then have it route to a windows 2000 dhcp server for an internal network ! is that what you are looking to do !
Or are you saying that you have a dhcp server and then a hardware router for your router insted of using a win2k server as a router ! well , will the router take the dhcp request from the server ! to be honest with you i have never tried that , but i know if you set up a static entry for the router to work with the your dchp server it might work ! , for an internal network ! but this could also be totaly out of what you where looking for and the question did i have enough coffee today is also a far out thing to say as well ! Take Care
Anthony Cabanas
Long Island Networking Technologies Inc acabanas@linettech.com
You could have a router for a dmz running dhcp on an external network and then have it route to a windows 2000 dhcp server for an internal network ! is that what you are looking to do !
Or are you saying that you have a dhcp server and then a hardware router for your router insted of using a win2k server as a router ! well , will the router take the dhcp request from the server ! to be honest with you i have never tried that , but i know if you set up a static entry for the router to work with the your dchp server it might work ! , for an internal network ! but this could also be totaly out of what you where looking for and the question did i have enough coffee today is also a far out thing to say as well ! Take Care
Anthony Cabanas
Long Island Networking Technologies Inc acabanas@linettech.com
Because if the dhcp client makes a request then you would be getting an dhcp address from the router Not the dhcp server , your router would be your dhcp server !
Anthony Cabanas
Long Island Networking Technologies Inc acabanas@linettech.com
Anthony Cabanas
Long Island Networking Technologies Inc acabanas@linettech.com
- Thread starter
- #8
Accessdabbler
Technical User
What is with all the bloody exclamation marks???
- Thread starter
- #9
Accessdabbler
Technical User
OK, GrnEyedLdy, I follow. What do you need to set up a DHCP relay service? Can any old 9X, NT or 2K Pro system do it or is it part of the 2K Server edition?
GrnEyedLdy
Instructor
Accessdabbler,
In order to make a 2000 server into a DHCP relay agent, you must configure RRAS.
1. Start|Programs|AdministrativeTools|Routing and Remote Access
2. Right-click your server's name and choose Configure and Enable Routing and Remote Access.
3. During the wizard, choose Manually Configured Server.
4. Now, in the Routing and Remote Access MMC, expand your server and click the (+) sign next to IP Routing.
5. Right-click General and choose New Routing Protocol.
6. Click DHCP relay agent and then click Ok.
7. Right-click DHCP relay agent in the left pane and choose Properties. Enter the IP address of the DHCP SERVER that you want the DHCP relay agent to communicate with, and then click Add.
8. Then enable the DHCP relay agent to 'listen' on the Interface by right-clicking DHCP relay agent and choosing New Interface...choose the Interface and click Ok.
Your DHCP SERVER will need to be configured with a scope for the remote subnet so that it can hand out address to clients from that subnet.
Have fun,
Patty
In order to make a 2000 server into a DHCP relay agent, you must configure RRAS.
1. Start|Programs|AdministrativeTools|Routing and Remote Access
2. Right-click your server's name and choose Configure and Enable Routing and Remote Access.
3. During the wizard, choose Manually Configured Server.
4. Now, in the Routing and Remote Access MMC, expand your server and click the (+) sign next to IP Routing.
5. Right-click General and choose New Routing Protocol.
6. Click DHCP relay agent and then click Ok.
7. Right-click DHCP relay agent in the left pane and choose Properties. Enter the IP address of the DHCP SERVER that you want the DHCP relay agent to communicate with, and then click Add.
8. Then enable the DHCP relay agent to 'listen' on the Interface by right-clicking DHCP relay agent and choosing New Interface...choose the Interface and click Ok.
Your DHCP SERVER will need to be configured with a scope for the remote subnet so that it can hand out address to clients from that subnet.
Have fun,
Patty
- Thread starter
- #12
Accessdabbler
Technical User
OK, I sort of follow you but I don't have Win2K Server. What you are saying is that I need to use Win2K Server to do this. But, since I already have a Server on the same segment, one would wonder why it isn't the DHCP Server?? I guess, in a large intranet, you may have multiple segments but want only one system to act as the DHCP server to allow for consistent IP addressing for all systems in the entire network.
GrnEyedLdy
Instructor
"I already have a Server on the same segment..."
What kind of server do you have on the segment? Is this the segment on the 'other' side of the router?
Remember, as NtrOP said, you can configure your router to act as the DHCP relay agent and allow it to pass DHCP Discover packets.
Patty
What kind of server do you have on the segment? Is this the segment on the 'other' side of the router?
Remember, as NtrOP said, you can configure your router to act as the DHCP relay agent and allow it to pass DHCP Discover packets.
Patty
- Thread starter
- #14
Accessdabbler
Technical User
My question is hypothetical. I don't have any servers. I'm still learning about networking.
All I meant was that if I have a server on the "near" side of the router setup to relay to a server on the "far" side, why wouldn't I just have the "near" server act as DHCP to all systems on that side? I answered my own question when I realized that you may want the "far" server to look after ALL DHCP addressing for the entire network.
The only router I've used is a broadband router that does not have the ability to forward broadcasts. This is why I must dream up these questions to further my understanding.
I wish I could get a copy of Win2K Server to play with (having only 2 computers at home doesn't justify installing it for good) to learn all its "Server" features. I may have to buy it anyway someday.
Thanks for all your help!
All I meant was that if I have a server on the "near" side of the router setup to relay to a server on the "far" side, why wouldn't I just have the "near" server act as DHCP to all systems on that side? I answered my own question when I realized that you may want the "far" server to look after ALL DHCP addressing for the entire network.
The only router I've used is a broadband router that does not have the ability to forward broadcasts. This is why I must dream up these questions to further my understanding.
I wish I could get a copy of Win2K Server to play with (having only 2 computers at home doesn't justify installing it for good) to learn all its "Server" features. I may have to buy it anyway someday.
Thanks for all your help!
GrnEyedLdy
Instructor
Accessdabbler,
OIC now...
Microsoft used to allow a free download of a 90 eval. copy of their 2000 OS's. Not sure if they still do. It would be worth a try to take a look around their site.
Good luck,
Patty
OIC now...
Microsoft used to allow a free download of a 90 eval. copy of their 2000 OS's. Not sure if they still do. It would be worth a try to take a look around their site.
Good luck,
Patty
GrnEyedLdy
Instructor
"a free download of a 90 eval. copy of their 2000 OS's."
Correction, that should have said 90 DAY eval, instead of 90 EVAL...
Correction, that should have said 90 DAY eval, instead of 90 EVAL...
jimbopalmer
Programmer
Access I use a combined DNS DHCP product that can sync a laptop's DNS name even though it's IP address changed, that is why I prefer to use a central DHCP server (with a backup) rather than let each subnet handle DHCP I tried to remain child-like, all I acheived was childish.
- Status