DHCP and IP Numbers ?
Hi ! I have a question about how DHCP is working. You see, I try to set up a small cluster of boxes to do some parallel computing. The Name Resolution in this cluster is supposed to work with DHCP. Things seem to run smoothly, but after some time, my parallel process is interrupted, with no error message at all. I `d like to know if DHCP reassigns new IPs after a certain amount of time and if this could interrupt my parallel processes (I tried both MPICH and rsh). Any suggestions ? Thanks, Jörg
On Fri, 2003-11-07 at 09:39, remote wrote:
Hi !
I have a question about how DHCP is working. You see, I try to set up a small cluster of boxes to do some parallel computing. The Name Resolution in this cluster is supposed to work with DHCP. Things seem to run smoothly, but after some time, my parallel process is interrupted, with no error message at all. I `d like to know if DHCP reassigns new IPs after a certain amount of time and if this could interrupt my parallel processes (I tried both MPICH and rsh).
Any suggestions ?
You should NEVER put servers on DHCP, servers should only ever have fixed addresses.
Thanks,
Jörg
-- Ken Schneider unix user since 1989 linux user since 1994 SuSE user since 1998 (5.2)
On Fri, Nov 07, 2003 at 09:51:34AM -0500, Ken Schneider wrote:
You should NEVER put servers on DHCP, servers should only ever have fixed addresses.
a lot of my machines have fixed adresses and a lot of them get them via DHCP. DHCP can also provide static entries... -- Stefan Seyfried Senior Consultant community4you GmbH, Chemnitz, Germany. http://www.community4you.de http://www.open-eis.com
i think he meant his cluster nodes are dynamically addressed, not his controller. we could have used a bit more info though :D i still don't see what this is doing on this list though. Benoit Gariod -----Original Message----- From: Ken Schneider [mailto:kschneider@rtsx.com] Sent: Friday, November 07, 2003 3:52 PM To: suse-security@suse.com Subject: Re: [suse-security] DHCP and IP Numbers ? On Fri, 2003-11-07 at 09:39, remote wrote:
Hi !
I have a question about how DHCP is working. You see, I try to set up a small cluster of boxes to do some parallel computing. The Name Resolution in this cluster is supposed to work with DHCP. Things seem to run smoothly, but after some time, my parallel process is interrupted, with no error message at all. I `d like to know if DHCP reassigns new IPs after a certain amount of time and if this could interrupt my parallel processes (I tried both MPICH and rsh).
Any suggestions ?
You should NEVER put servers on DHCP, servers should only ever have fixed addresses.
Thanks,
Jörg
-- Ken Schneider unix user since 1989 linux user since 1994 SuSE user since 1998 (5.2) -- Check the headers for your unsubscription address For additional commands, e-mail: suse-security-help@suse.com Security-related bug reports go to security@suse.de, not here
Joerg, DHCP does not assign a different IP address to a computer while the lease is active. The clients, while on the network, will periodically renew their lease and retain their address. I am pretty confident that your problem is somewhere else Markus ----------------------------------------------- My other computer is a 2200 CPU Mac G5 cluster. More about the worlds fastest academic computer: http://www.cs.vt.edu/
-----Original Message----- From: remote [mailto:remote@leat.ruhr-uni-bochum.de] Sent: Friday, November 07, 2003 9:40 AM To: suse-security@suse.com Subject: [suse-security] DHCP and IP Numbers ?
Hi !
I have a question about how DHCP is working. You see, I try to set up a small cluster of boxes to do some parallel computing. The Name Resolution in this cluster is supposed to work with DHCP. Things seem to run smoothly, but after some time, my parallel process is interrupted, with no error message at all. I `d like to know if DHCP reassigns new IPs after a certain amount of time and if this could interrupt my parallel processes (I tried both MPICH and rsh).
Any suggestions ?
Thanks,
Jörg
Hi,
some time, my parallel process is interrupted, with no error message at all. I `d like to know if DHCP reassigns new IPs >after a certain amount of time and if this could interrupt my parallel processes (I tried both MPICH and rsh).
Yes, it could, but it should not. Set default lease time and max lease time accordingly (in seconds). If the client dhcp works correctly, it should ask the dhcp server for the same IP again, when the lease time is over, the dhcpd checks its database and re-assigns the same IP to the client. If the clients get different addresses each time it might interrupt processing. Use "man dhcp-options" for info about the parameters. Ciao, Dieter
The minimum amount of time before any node will be assigned a new IP should be the lease time configured on the DHCP server. You could try a couple of things: increasing the IP range ("pool"), so as to not force reuses because the server is running shoirt of available IP addresses to hand out, and increasing the lease time itself. i think that the default behaviour of the dhcp client to to request the IP it previously had, so that should help. Benoit Gariod -----Original Message----- From: remote [mailto:remote@leat.ruhr-uni-bochum.de] Sent: Friday, November 07, 2003 3:40 PM To: suse-security@suse.com Subject: [suse-security] DHCP and IP Numbers ? Hi ! I have a question about how DHCP is working. You see, I try to set up a small cluster of boxes to do some parallel computing. The Name Resolution in this cluster is supposed to work with DHCP. Things seem to run smoothly, but after some time, my parallel process is interrupted, with no error message at all. I `d like to know if DHCP reassigns new IPs after a certain amount of time and if this could interrupt my parallel processes (I tried both MPICH and rsh). Any suggestions ? Thanks, Jörg
participants (6)
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Benoit Gariod -
Dieter Kirchner -
Ken Schneider -
Markus Lorch -
remote -
Stefan Seyfried