# Using an NTP-server behind NAT, it works! After testing a lot. No not many routers/OS can handle it. Really not many

**URL:** <https://community.ntppool.org/t/using-an-ntp-server-behind-nat-it-works-after-testing-a-lot-no-not-many-routers-os-can-handle-it-really-not-many/4580>\
**Category:** Server operators\
**Created:** [July 15, 2026, 4:25pm UTC](https://community.ntppool.org/t/using-an-ntp-server-behind-nat-it-works-after-testing-a-lot-no-not-many-routers-os-can-handle-it-really-not-many/4580 "2026-07-15T16:25:04Z")\
**Posts on this page:** 1\
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**Author:** ![mlichvar](https://avatars.discourse-cdn.com/v4/letter/m/e79b87/32.png) [@mlichvar](https://community.ntppool.org/u/mlichvar)\
**Post date:** [July 16, 2026, 5:52am UTC](https://community.ntppool.org/t/using-an-ntp-server-behind-nat-it-works-after-testing-a-lot-no-not-many-routers-os-can-handle-it-really-not-many/4580/4 "2026-07-16T05:52:23Z")

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> [@Bas](#):
>
> 96K connections 🤣

That suggests you still have some connection tracking for NTP, possibly created by the server responses. The server traffic should not increase the number of connections at all. With nftables it needs two notrack rules, one for incoming direction, one for the outgoing direction, see the example in this post: [Joining the pool kills my Internet - #21 by mlichvar](https://community.ntppool.org/t/joining-the-pool-kills-my-internet/1237/21)

Use the `nft list ruleset` command to verify the rules generated from the OpenWrt firewall config.

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