Another NTP client failure story


I came across this funny story


Sadly there are probably lots more out there that have done the same thing.

Right now I have a branch of Cisco that makes IoT thingies that appears to be pounding my NTP server with requests from a very specific netblock. When you log it based on IP they stick out like a sore thumb, but compared to the overall amount of requests it’s not worth getting in a huge battle over. I’ve tried contacting them with no luck… Every now and then I block that netblock hoping someone will raise an eyebrow and wonder, but maybe they went one step further and hard-coded multiple IPs or something… Queries don’t let up even when blocked, so definitely hard-coded and definitely not a well behaved client.


Jasper Technologies and

I don’t think they’ve hardcoded anyone’s IPs – I think they’re doing normal DNS lookups and slamming the entire Pool that hard.

My hope(?) is that they actually have like a billion devices behind a small NAT block.


Yes, that’s them! That’s the netblock!

Even when blocked (for weeks) they keep hitting my IP persistently…

We’ve had Netgear, SMC, D-Link, TP-Link, and Snapchat all make “coding mistakes”… Seems only right Cisco gets tossed in the mix…


Lurker here in the community from Network Time Foundation. Love to know what part of Cisco this is so I can go chase them down. I work for NTF, and these are opportunities to find funding for the Pool and for NTF.

IMHO, these huge orgs need to be reminded of the rules, and especially that they should be supporting the NTP Pool (and NTF) to keep the service available and scaling to the needs of users (IoT- OMG!)

Steve Sullivan


It’s Jasper Technologies – it was a company acquired by Cisco in 2016. Their website now uses “Cisco Jasper” branding. (I only use their old name because they haven’t updated their IP addresses’ whois information since 2015.)


Still a candidate for their own Vendor Zone for the DNS though, right?


At the very least, yes… You might be able to not only talk Jasper into one, but Cisco too (I don’t know what their routers and such use as default).

Though I’m curious what on earth is making all those queries, if it’s just some IoT things or if it’s more, and if they are even aware of it.


I was put in contact with someone at Cisco Jasper today. I want to have a conversation with him in the next week to discuss the NTP Pool and discuss Vendor Zones.


If it’s all coming from one netblock then presumably it would be easy enough for them to make a local NTP server. If the devices are hard-coded with then they would have to spoof the DNS queries but still, they should be able to do it somehow.


That’s good news! Please keep us updated, I’m curious to hear what is going on within their network.


Hi there Pool!

I made contact with Cisco Jasper.

Cisco Jasper customers are Automotive manufacturers using the Cisco Jasper network to connect automobiles and mobile devices for internet service and diagnostics. Endpoints could be using any local time-source, so that is not an issue that Cisco Jasper can control.

They asked if we can provide how much traffic you guys are seeing (report form to share internally). This would be used to float the idea of and prove the need for Vendor Zone within Cisco Jasper.

I must point out, my contact said he has been using this for over 3 years and this is the first he has heard about Pool problems and the availability of the vendor zone. I think much of the time that you guys get slammed, it is because of a lack of awareness about the pool and how to use it. With IoT coming into its own, the slamming will increase otherwise:).

Can someone provide the data Cisco Jasper requested and I will start the process of negotiating a vendor zone with them?

Also, as an aside, My contact at Cisco Jasper says that Cisco uses internal time sources for their own employee equipment (desktops, switches, etc). It would be helpful for me to know if that is indeed the case from your network analysis perspectives.



Well, as an example, just now I ran tcpdump on one of my Pool servers – US zone, speed setting 500 Mbps – and got 1000 packets from in 43 seconds.

And I dropped almost all of them. Using default rate limiting settings, I’m pretty close to a black hole for them. I wonder if they even get usable time from the Pool.


$ nice ntpq -c "mrulist mincount=1300000 sort=-count"
Ctrl-C will stop MRU retrieval and display partial results.
Retrieved 31 unique MRU entries and 0 updates.
lstint avgint rstr r m v  count rport remote address
     1      1  3f0 L 3 1 4641911 19375 [redacted]
    12      0  3b0 . 3 4 3650010 33353 [redacted]
     0      1  3f0 L 3 3 3429535 55406 [redacted]
     1      1  3f0 L 3 4 3284233 34048
     7      1  3f0 L 3 4 3280771 42550
     2      1  3f0 L 3 4 3267119  6491
     8      1  3f0 L 3 4 3264288 13700
     2      1  3f0 L 3 4 3254222 53455
     2      1  3f0 L 3 4 3251573 55287
     2      2  3f0 L 3 3 3231497 56611 [redacted]
     3      1  3f0 L 3 4 3230892 10878
     2      1  3f0 L 3 4 2902637 15685
     1      2  3f0 L 3 3 2832740   495 [redacted]
     2      2  3f0 L 3 3 2311053 15478 [redacted]
     1      1  3f0 L 3 3 2253325 46383 [redacted]
     0      1  3b0 . 3 4 2102937 18590 [redacted]
     1      2  3b0 . 3 4 1957184 34323
    25      2  3f0 L 3 4 1927618  7179
    22      2  3b0 . 3 4 1905523   123
    10      2  3b0 . 3 4 1896736 13001
     0      1  3f0 L 3 3 1759819  7475 [redacted]
     7      2  3b0 . 3 4 1542396 36363
     9      2  3b0 . 3 4 1496631   123
     2      2  3f0 L 3 4 1482457 17984
     1      2  3f0 L 3 4 1468126 10073
     8      2  3f0 L 3 4 1451252 26659
     0      2  3f0 L 3 4 1445748   123
    23      2  3b0 . 3 4 1436378   123
     2      3  3f0 L 3 4 1352490 46048 [redacted]
     5      2  3f0 L 3 4 1332150 45026
    14      2  3b0 . 3 4 1301119   123


My server in the US zone received from the network about 90 million requests in the last three weeks. That’s about 50 packets per second on average. It has enabled rate limiting and it responded to more than 90% of the requests. To me it looks like a larger number of clients behind NAT, rather than a small number of broken clients.

On servers in few other zones the rate of requests from this network seems to be much smaller.


Are they routing all these devices through their own network?

I posted some stats in another thread, I was getting around 500k/day from their netblock, US server 100Mb setting… Which equates to around 5-6 a second, which is about 1/10th of @mlichvar and that makes sense as he’s at 1Gb setting for the pool. Likewise for @mnordhoff that was at 23/s @ 500Mb (granted his sample time was just those 43 seconds, but it is still close enough to mlichvar’s to confirm overall rate).

If we are to extrapolate from a chart mlichvar posted in another thread, that a single 1Gb server handles 0.95% of the US traffic, and they are querying the whole pool equally (which appears to be the case)… So they are hitting just the US pool at: 50 / 0.95% * 86400 = 454,736,842 queries per day…

Likewise from the chart, the US pool receives about 389,474 queries per second, which puts just Jasper at using about 1.4% of that total usage (assuming they are only querying the US pool). If they are querying the global pool, which receives about 509617 QPS, then that number drops down to 1%… I estimated 1% from my own server stats, which I do receive traffic from all over the world, so that would fall in line with the above estimates…

One company, creating 1% of the total GLOBAL pool traffic… Does the pool serve only 100 clients? No… It serves hundreds of millions…

Last time I posted numbers my server (@ 100Mb) was seeing ~2.4 Million unique IPs a day… A 1Gb server would theoretically see about 24 Million (Maybe @mlichvar has stats he can post on daily unique IPs on his servers) … I’m not sure the 0.95% would hold true as that would be about 2.5 Billion IPs, which is over half the IPv4 address space. There would be a fair amount of overlap as the same devices would be querying multiple servers in a day (either regular polling via NTP, or some regular polling interval doing SNTP)… If you divide by 5 (as a rough guess of how many servers one IP might query in a day), you get around 500 Million IPs which is more believable from the existing numbers.

The only reason it’s not a DDoS is because the queries are coming from a relatively small group of IPs. But as I pointed out they are creating a very noticable amount traffic. Any NTP server which has the ‘limited’ statement in its default configuration (which is probably every one), is dropping packets from the Jasper netblock. I believe the default ‘discard’ average query rate is 8-seconds (which is more than generous for how NTP should operate). Their query rate per-IP is way too high, plain and simple. Even if traffic continues to grow from those IPs, the only thing that is going to happen is more packets are going to get dropped. That’s assuming the pool servers are using the regular NTP distribution, I know nothing about Chrony, but I’m going to assume it’s very similarly configured / rate limited. Also, it’s not all the ~1,000 IPs in Jasper’s netblock, last time I logged it was around only 140 IPs creating all the traffic…

I just re-enabled logging this morning… I’ll let it run for a day and PM you some specific IPs and traffic numbers. That might help determine exactly what is going on.

*Note: Any mistakes or things that don’t make sense above is because I’m still drinking my coffee this morning… lol.