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.

Reply to
Loading thread data ...

" snipped-for-privacy@hotmail.com" hath wroth:

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.

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.

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.

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.

Reply to
Jeff Liebermann

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).

Reply to
Jeff Liebermann

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.

Reply to

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

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

Reply to

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.