The NTP pool addresses have very short caching lifespans, and they may even have expired before they reach your router. The number can be reduced by about 15 % if your router has a caching DNS server and you’re extremely lucky with request timings. Multiply this by one request per 5 seconds throughout the day, and then finally add up the monthly figure and you’ll end up at 715,4 MB. An NTP request is another 90 bytes plus a 90 byte response. The six DNS requests add up to about 75 bytes each with a median response size of 125 bytes. I find it interesting that TP-Link chose to use the Australia and New Zealand server pools in their firmware globally. They also request that vendors don’t check more often than every 5 minutes at the most. ), and emphasize that they “must absolutely not use the default zone names”. The NTP Pool project asks device manufacturers and vendors to register (and optionally sponsor) their own pools through the service (e.g. The IP addresses are owned by universities in Japan, Colorado US, and Sweden respectively. The second is the Australian and New Zealand public NTP project time server pools. National Institute of Standards and Technology ( NIST). The first sets of servers are operated by the U.S. TP-Link has hardcoded the following non-configurable NTP servers and server pools in their firmware: Wasting 715,4 MB per month for a single string on a web administration interface that the customer is only likely to visit once a year is outright stupid. (Except for providing a DHCP server when they fail to detect another DHCP server, but that’s irrelevant for this discussion.) I may be mistaken, but as far as I’ve been able to observe by studying the network traffic and behaviors of my TP-Link RE650 – it only controls the string “Internet Status: Connected”. TP-Link repeaters don’t seem to modify their behavior based on whether there’s a working internet connection or not. Instead, they misuse public infrastructure provided by volunteers (like the NTP project pool servers), universities, and the U.S. The feature as TP-Link has implemented it’s overly aggressive, and they don’t even have the decency to direct the traffic at their own servers. These types of tests are normally implemented over HTTP and only check against remote servers every 5–45 minutes. They misuse DNS and NTP as a stand-in for an internet connectivity test feature. This behavior isn’t a bug from TP-Link’s perspective. Update ( ): TP-Link have issued firmware updates to address this issue. For comparison, a 5-minute check would be considered a pretty aggressive checking interval, and would only consume 11,92 MB per month. This means your TP-Link product is using about 1,38 KB every 5 seconds - or 23,85 MBs per day - on timekeeping. (If you power cycle or suspend your device, it will send one additional request.) An always-on Windows client sends 1 DNS and 1 NTP request once a week. TP-Link’s firmware doesn’t have any sort of DNS caching, and they query DNS about 6 NTP server pool addresses every 5 seconds followed by an NTP request to one of them. To put this number in context: an always-on Windows device will use around 1,6 KB per month on NTP. NTP is the network time protocol used to synchronize clocks across the web. The firmware of some TP-Link repeaters - but not routers - including all 2017 models are very talkative on NTP, to a total of 715,4 MB per month. By design, TP-Link firmware sends six DNS requests and one NTP query every 5 seconds, for a total of 715,4 MB per month. You should probably avoid TP-Link products if you’re on a tight bandwidth budget.
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