NTP with 2 Routers

I understand that Netgear Routers have had a rather poor history of
NTP implementation (apparently the had a model or firmware that was
flooding requests to a university's NIST server.

In any event, I use my WGR614v7 solely as an AP and a switch. It does
not serve DHCP and connects LAN to LAN to another wireless router, a
Linksys which serves as the gateway and DHCP server. Almost
everything works fine for this configuration except that the Netgear
has some notification applications that rely on NTP and since the
router is reporting a time/date in 2003 I have to assume that this
data isn't getting requested or getting through without this router
having the WAN connection. I thought, maybe if I opened port 123 on
the gateway router and forwarded to the Netgear's IP that NTP would
work but the clock does not update. I feel certain that if I
exchanged the position (responsibilities) of the 2 routers, that this
would work but I was hoping someone would have an idea to save me some
reconfiguration. The Linksys router doesn't use a NTP implementation
at all.

"(E-Mail Removed)" <(E-Mail Removed)> hath wroth:

>I understand that Netgear Routers have had a rather poor history of
>NTP implementation (apparently the had a model or firmware that was
>flooding requests to a university's NIST server.

Yep. Same with Dlink and some others. At least Netgear admited that
they caused the problem and did something to help fix it. Dlink
stonewalled for months and finally had to get sue.

>In any event, I use my WGR614v7 solely as an AP and a switch.

No router section in use? I don't think their NTP implimentation will
work that way. The NTP requests go out port 123 via the WAN port, not
the LAN. Since the WAN port is not connected to anything in your
configuration, it will not get NTP replies. I'm not 100.0% sure about
this, but a bit of sniffing of the initial power on traffic should
identify the NTP packets, whether they're on the LAN or WAN, and where
they're going.

>It does
>not serve DHCP and connects LAN to LAN to another wireless router, a
>Linksys which serves as the gateway and DHCP server. Almost
>everything works fine for this configuration except that the Netgear
>has some notification applications that rely on NTP and since the
>router is reporting a time/date in 2003 I have to assume that this
>data isn't getting requested or getting through without this router
>having the WAN connection. I thought, maybe if I opened port 123 on
>the gateway router and forwarded to the Netgear's IP that NTP would
>work but the clock does not update.

Well, if you're going through a different router, you'll need to open
port 123 on that router. Otherwise, the requests will go out, but
nothing will be accepted coming back.

>I feel certain that if I
>exchanged the position (responsibilities) of the 2 routers, that this
>would work but I was hoping someone would have an idea to save me some
>reconfiguration. The Linksys router doesn't use a NTP implementation
>at all.

No clue on what to do with your existing configuration. If your
unspecified model Linksys router happens to have a NTP relay feature,
you can use that to act as a local NTP server. However, that will
only work if there were some way to point the WGR614v7 to the IP
address of the NTP relay and I don't recall seeing such an option.

If you have a Linux box or some computer on full time, you can setup
an NTP relay, where all your local clients get their time updates from
this Linux box. It would need to be on full time, which may be a
problem. Even so, it would require that the WGR614v7 send and accept
NTP packets on it's LAN ports, which I don't think is possible.

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Mon, 19 Mar 2007 10:06:36 -0700, Jeff Liebermann
<(E-Mail Removed)> wrote:

>No router section in use? I don't think their NTP implimentation will
>work that way. The NTP requests go out port 123 via the WAN port, not
>the LAN. Since the WAN port is not connected to anything in your
>configuration, it will not get NTP replies.

Argh. That's totally wrong. The NTP request goes out on any port
between 1024 thru 65,000. It's the reply that comes back on port 123.
Sorry about the muddle.

I just did a fast sniff on my office LAN for NTP traffic from my
WRT54G running DD-WRT v23 SP2. No NTP traffic at all on the LAN side
within 10 minutes of power on. I'm too lazy to setup the sniffer on
the WAN side (because I can't find a working ethernet hub anywhere).

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 (E-Mail Removed)
# http://802.11junk.com (E-Mail Removed)
# http://www.LearnByDestroying.com AE6KS

On Mar 19, 7:59 pm, Jeff Liebermann <j...@comix.santa-cruz.ca.us>
wrote:
> On Mon, 19 Mar 2007 10:06:36 -0700, Jeff Liebermann
>
> <j...@comix.santa-cruz.ca.us> wrote:
> >No router section in use? I don't think their NTP implimentation will
> >work that way. The NTP requests go out port 123 via the WAN port, not
> >the LAN. Since the WAN port is not connected to anything in your
> >configuration, it will not get NTP replies.
>
> Argh. That's totally wrong. The NTP request goes out on any port
> between 1024 thru 65,000. It's the reply that comes back on port 123.
> Sorry about the muddle.
>
> I just did a fast sniff on my office LAN for NTP traffic from my
> WRT54G running DD-WRT v23 SP2. No NTP traffic at all on the LAN side
> within 10 minutes of power on. I'm too lazy to setup the sniffer on
> the WAN side (because I can't find a working ethernet hub anywhere).
>
> --
> # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
> # 831-336-2558 j...@comix.santa-cruz.ca.us
> #http://802.11junk.com j...@cruzio.com
> #http://www.LearnByDestroying.com AE6KS

Jeff, thanks for the try. Looks like I'll probably just switch the
routers around eventually. The Linksys is an old 802.11b router that
doesn't keep time for any purposes anyway.

<(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
> I understand that Netgear Routers have had a rather poor history of
> NTP implementation (apparently the had a model or firmware that was
> flooding requests to a university's NIST server.
>
> In any event, I use my WGR614v7 solely as an AP and a switch. It does
> not serve DHCP and connects LAN to LAN to another wireless router, a
> Linksys which serves as the gateway and DHCP server. Almost
> everything works fine for this configuration except that the Netgear
> has some notification applications that rely on NTP and since the
> router is reporting a time/date in 2003 I have to assume that this
> data isn't getting requested or getting through without this router
> having the WAN connection.

it is because the requests go out on the WAN link as suggested by Jeff.

i "fixed" this on an old Netgear (MR814) - plug the WAN port into one of the
LAN ports with a local Ethernet patch lead, and give the WAN port an address
that matches the local LAN range.

Note - it doesnt matter that the LAN and WAN have addresses in the same
subnet - not sure if that is a design feature....

I thought, maybe if I opened port 123 on
> the gateway router and forwarded to the Netgear's IP that NTP would
> work but the clock does not update. I feel certain that if I
> exchanged the position (responsibilities) of the 2 routers, that this
> would work but I was hoping someone would have an idea to save me some
> reconfiguration. The Linksys router doesn't use a NTP implementation
> at all.

NTP should just flow thru a typicl SOHO router without needing a configured
forwarding rule.
>
--
Regards

(E-Mail Removed) - replace xyz with ntl