Multiple dhcp relay process

classic Classic list List threaded Threaded
4 messages Options
Reply | Threaded
Open this post in threaded view
|

Multiple dhcp relay process

Renuka Devi
Hi all,

Can someone please let me know if it's possible to run multiple dhcp relay process with different set of downstream, upstream interfaces and server IPs ?

Like more than one relay process or instance running for v4 or v6 using ISC DHCP?

Thanks,
Renuka

_______________________________________________
ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.

dhcp-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users
Reply | Threaded
Open this post in threaded view
|

Re: Multiple dhcp relay process

Simon Hobson
On 5 May 2021 17:11:53 BST, Renuka Devi <[hidden email]> wrote:
>Hi all,
>
>Can someone please let me know if it's possible to run multiple dhcp
>relay
>process with different set of downstream, upstream interfaces and
>server
>IPs ?

Yes, provided they don't share any interfaces at all. Depending on your distro, it may need some effort to get two different configs going.

Simon

_______________________________________________
ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.

dhcp-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users
Reply | Threaded
Open this post in threaded view
|

Re: Multiple dhcp relay process

Renuka Devi
Thanks Simon for your quick response.

Do we have to enable any flags or modify ISC dhcp relay code to make it working ?

Any inputs on code changes needed will be helpful to me.

Thanks,
Renuka 

On Wed, May 5, 2021 at 10:29 AM Simon Hobson <[hidden email]> wrote:
On 5 May 2021 17:11:53 BST, Renuka Devi <[hidden email]> wrote:
>Hi all,
>
>Can someone please let me know if it's possible to run multiple dhcp
>relay
>process with different set of downstream, upstream interfaces and
>server
>IPs ?

Yes, provided they don't share any interfaces at all. Depending on your distro, it may need some effort to get two different configs going.

Simon

_______________________________________________
ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.

dhcp-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users

_______________________________________________
ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.

dhcp-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users
Reply | Threaded
Open this post in threaded view
|

Re: Multiple dhcp relay process

Simon Hobson
Renuka Devi <[hidden email]> wrote:

> Do we have to enable any flags or modify ISC dhcp relay code to make it working ?

Asa far as I know (I don't use it myself, but it shares code with the client and server), all you have to do is invoke it with arguments that mean each instance uses different config, PID, etc files. I suspect most distro startup files don't allow for this, so you'll be needing to roll your own.

There is one area I don't know about. I thought that the relay agent might have to listen on the interface through which it talks to the server - but I'm not sure about that. If it does, then the upstream interfaces need to be different.
But it's also possible that it uses ordinary unicast packets passed through the hosts IP stack to talk to the server(s).
I raise this as I have a vague memory of seeing issues with this discussed here, but it's only vague. Hopefully someone with a better grasp can shed some light.

So as I read the man page, and if it uses the host IP stack, then you'd invoke the different instances like this :

dhcrelay -4 [some options] -i eth0 -i eth1 192.168.1.123
dhcrelay -4 [other options] -i eth2 192.168.57.66

I see it doesn't have a config file or any storage (leases file), so those problems are gone. If your process management system uses PID files, then you'll need to make sure that they are different.

Simon

_______________________________________________
ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.

dhcp-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users