How to get timing for DHCP discover/offer/ack/request ?

[Marlon Brown]

Imagine I have WinXP on a small branch office (70 PC's) and network fellow
persists that I should put a DHCP server on the branch office (currently
DHCP server is the main office, connected via T1).

I would like to get DHCP discover/offer/ack/request time from
clientBranchOffice to DHCPServerMainOffice (T1) and demonstrate that timing
to acquire IP address is acceptable.

Anybody there has a good idea on the best method to acquire such DHCP
discover/offer/ack/request parameters ?
By launching netmon and doing ipconfig /release then ipconfig /renew I
should have a realistic sample of such data, correct ?

 

[Galen]

In Marlon Brown <[email protected]> had this to say:

My reply is at the bottom of your sent message:

Imagine I have WinXP on a small branch office (70 PC's) and network
fellow persists that I should put a DHCP server on the branch office
(currently DHCP server is the main office, connected via T1).

I would like to get DHCP discover/offer/ack/request time from
clientBranchOffice to DHCPServerMainOffice (T1) and demonstrate that
timing to acquire IP address is acceptable.

Anybody there has a good idea on the best method to acquire such DHCP
discover/offer/ack/request parameters ?
By launching netmon and doing ipconfig /release then ipconfig /renew I
should have a realistic sample of such data, correct ?

Yes, I think so, but will that satisfy the person questioning you? Perhaps
you should ask why they're asking you this question.

Galen

 

[Phillip Windell]

The "network fellow" is correct and the "timings" don't have anything to do
with it and don't even matter.

The problem is that the WAN link can go down at anytime for any reason. If
that happens and the DHCP is not Local then your Office LAN has just had it
throat slit. For the same reason each Site should have its own DC. Active
Directory Sites are used to handle the replication between the DCs over the
WAN link. The LAN can survive for a considerable time without the
"replication" if the WAN link goes down, but it cannot survive very log
without DC services or DHCP. The one Server can be a DC and run DHCP, DNS,
and WINS perfectly fine. The management of such a Server is minimal unless
you create additional "complexities" and "work" by your own doing.

My DCs (with DHCP, WINS, & DNS) are the least "touched" machines on my
network.

 

[Herb Martin]

Imagine I have WinXP on a small branch office (70 PC's) and network fellow
persists that I should put a DHCP server on the branch office (currently
DHCP server is the main office, connected via T1).

Chances are if you have a server there, it should
be a DHCP server in SOME cases.

How do you expect the client broadcasts to reach
through the routers, across the WAN, and reach the
centralized DHCP server?

There are basically two ways:

1) Intervening routers must propagate
the DHCP_DISCOVER broadcasts

OR

2) You place a DHCP Relay Agent on the local
network (with the clients).

Broadcasts across WANs MAY be a poor idea.
Putting a local DHCP relay agent is almost as much
trouble as just putting the DHCP server locally.

On the other hand, if you have dozens of such sites
and wish to avoid keeping up with all those DHCP
servers the Relay agent can make more sense.

Also note, that many modern routers may be able to
function as "relay agents" even if they don't call it
that --- things like "DHCP helper address" may offer
this capability.

I would like to get DHCP discover/offer/ack/request time from
clientBranchOffice to DHCPServerMainOffice (T1) and demonstrate that timing
to acquire IP address is acceptable.

NetMon is your friend. The one from SMS-BACKOffice
can even run an agent on a client for collecting ALL of the
data.

EtherReal may be useful (search Google.)

BEWARE: Using an network monitory on SOME networks
may get your fired or reprimanded.

Anybody there has a good idea on the best method to acquire such DHCP
discover/offer/ack/request parameters ?

NetMon etc does this.

By launching netmon and doing ipconfig /release then ipconfig /renew I
should have a realistic sample of such data, correct ?

Yes. It will capture that data. With proper filters you can
capture or view ONLY that data as well.