[ntp:questions] (Software) timeserver for windows being broadcast-able incl. keys

Tom Smith smith at cag.zko.hp.com
Fri Mar 16 14:31:12 UTC 2007


Erik wrote:
> On 15 mrt, 17:21, Tom Smith <s... at cag.zko.hp.com> wrote:
>>> broadcast 145.47.51.127 key 1
>>> broadcast 145.47.51.255 key 1
>>> broadcast 145.47.52.127 key 1
>>> broadcast 145.47.53.127 key 1
>> That's the right idea, but the second one above already
>> includes the first.
>>
>> Your network configuration seems a little strange.
>> What is the address and netmask of your server (or
>> the addresses and netmasks if it has multiple interfaces)?
>> You should probably just broadcast to whatever subnet(s)
>> it is on. You need one broadcast statement for each
>> interface on the server.
>>
> 
> Hi Tom
> 
> there is one network-card in the server that connects to the network
> and has access to the network segments mentioned above
> The IP-data of this server (PC) is (ipconfig-output):
> 
> IP-adres . . . . . . . . . . . . . . .: 145.47.54.146
> Subnetmask . . . . . . . . . . . .: 255.255.255.128
> Standaardgateway . . . . . . . .: 145.47.54.129
> 
> Does this answer your question?

Yes. That answers the question. With that configuration,
in order to reach any of the clients, the packets that the
server sends will have to be routed and cannot (usually) be
broadcast. The server can (usually) only broadcast to its
own subnet(s).

That said, there are, of course, exceptions. I believe
that if the subnets are, in fact, all on the same VLAN,
you may be able to send a broadcast addressed to a
network wider than the subnet defined by the server's
netmask to any other network on the VLAN. In that case,
you could use the single broadcast address 145.47.63.255
to reach all of your clients. It might work and it might not.

The second exception is if your routers are configured
route broadcast messages to be beyond the subnet
on which they originate. In that case, you could again
use the single broadcast address 145.47.63.255 or
the 3 individual broadcast addresses (2 through 4 in
your list). Again, it might or might not work in your
existing network configuration.

What will work, without question, is not using
broadcast in the first place. You will have to work
with the company who supplied your systems to fix
the problem. You should continue this discussion
with them. This is really no longer about NTP.
It is about your network design.

-Tom




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