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

Danny Mayer mayer at ntp.isc.org
Sat Mar 17 03:34:28 UTC 2007


Tom Smith wrote:
> 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

This is beginning to sound like he should be using Multicast rather than
Broadcast. It's a lot more controllable and directable to do what he needs,

Danny



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