HI there,

the well-known port (udp 123) on my ntp server is blocked by a fire wall. my 
question is if i can use a different port on the server for ntpd to listen to 
and of course the client also need to be configured to send request to that 
port.

thanks.

-jd

On 2004-08-12, JIANDONG YANG, BLOOMBERG/ 499 PARK wrote:

> the well-known port (udp 123) on my ntp server is blocked by a fire
> wall. my question is if i can use a different port on the server for
> ntpd to listen to and of course the client also need to be configured
> to send request to that port.

nptd only works over port 123/UDP. And there is no good reason for your
firewall admins to refuse to allow connections via that port (especially
since both the source and destination ports are fixed). 

NTP is intended to be hierarchical. Your organization should be
providing a local NTP server (which is synced to outside servers) for
everyone on your LAN to use.

-- 
Steve Kostecke <kostecke@ntp.org>

"JIANDONG YANG, BLOOMBERG/ 499 PARK" <JYANG6@bloomberg.net> wrote in message 
news:mailman.24.1092344556.1754.questions@ntp.org...

> the well-known port (udp 123) on my ntp server is blocked by a fire wall. 
> my
> question is if i can use a different port on the server for ntpd to listen 
> to
> and of course the client also need to be configured to send request to 
> that
> port.

    Why not just open port 123 on the firewall? If the administration of the 
firewall won't open the port, isn't it safe to assume that they don't want 
NTP passing through the firewall? Presumably the firewall is administered by 
people with the authority to determine what protocol pass on the network.

    DS

David Schwartz <davids@webmaster.com> wrote:

> "JIANDONG YANG, BLOOMBERG/ 499 PARK" <JYANG6@bloomberg.net> wrote in message 
> news:mailman.24.1092344556.1754.questions@ntp.org...

>> the well-known port (udp 123) on my ntp server is blocked by a fire wall. 
>> my
>> question is if i can use a different port on the server for ntpd to listen 
>> to
>> and of course the client also need to be configured to send request to 
>> that
>> port.

>     Why not just open port 123 on the firewall? If the administration of the 
> firewall won't open the port, isn't it safe to assume that they don't want 
> NTP passing through the firewall? Presumably the firewall is administered by 
> people with the authority to determine what protocol pass on the network.

Authority yes, understanding.. maybe..

I have seen more than one case with NTP blocked in networks because of
network / firewall admins being unaware of NTP or thinking that NTP to
systems beyond 'their' routers needs to be blocked because otherwise NTP
traffic to those routers might be spoofed when they just learned this great
new way to actually have the correct time on 'their' routers.

                                          Koos van den Hout

-- 
Koos van den Hout, herding Suns and networks as koos@cs.uu.nl
+31-30-2534104              PGP keyid 0x27513781
http://idefix.net/~koos/            Use PGP when possible!
Camp Wireless, wireless Internet access at campsites http://camp-wireless.org/