How does le computer know qui device on le network to query? How does le par défaut gateway factor into this? Pretty much, **what is le chain of events that occurs quand a computer tries to obtain an IP address using DHCP**?
The reason I ask is parce que Je suis trying to figure out how to best set up a redundant DHCP server, in case le original fails for whatever reason.
Comment un ordinateur obtient-il une adresse IP via DHCP ?
Re: Comment un ordinateur obtient-il une adresse IP via DHCP ?
It ne know what device to query. Thus it broadcasts its request to le entire subnet. The DHCP server is listening for a certain type of communication et quand it hears that spécifique broadcast it begins le DHCP conversation avec le device that broadcasted its request. Take a look at le [DORA process](http://www.scribd.com/doc/24445850/DORA-Process-in-DHCP-DHCP-D-Iscover-DHCP-O-Ffer) for more information.
DORA stands for:
- [**D** iscovery](http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_discovery)
- [**O** ffer](http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_offer)
- [**R** equest](http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_request)
- [**A** cknowledgement](http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_acknowledgement)
As for le gateway, it *can* come into play seulement si it explicitly forwards DHCP traffic to another subnet. That feature is usually called [DHCP Relay](http://www.tech-faq.com/dhcp-relay-agents.html). Otherwise le gateway ignores le broadcast DHCP message juste like it ignores chaque autre broadcast message.
As for redundant DHCP servers, you'll want to keep them les deux on le même subnet et probably use le [80/20 rule](http://technet.microsoft.com/en-us/library/cc958936.aspx). Vous pouvez set up failover si [you're using CentOS as your DHCP server](http://www.howtoforge.com/how-to-set-up-dhcp-failover-on-centos5.1).
DORA stands for:
- [**D** iscovery](http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_discovery)
- [**O** ffer](http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_offer)
- [**R** equest](http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_request)
- [**A** cknowledgement](http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_acknowledgement)
As for le gateway, it *can* come into play seulement si it explicitly forwards DHCP traffic to another subnet. That feature is usually called [DHCP Relay](http://www.tech-faq.com/dhcp-relay-agents.html). Otherwise le gateway ignores le broadcast DHCP message juste like it ignores chaque autre broadcast message.
As for redundant DHCP servers, you'll want to keep them les deux on le même subnet et probably use le [80/20 rule](http://technet.microsoft.com/en-us/library/cc958936.aspx). Vous pouvez set up failover si [you're using CentOS as your DHCP server](http://www.howtoforge.com/how-to-set-up-dhcp-failover-on-centos5.1).