Sometimes NAT Loopback Stops Working

I'm relatively new to Eero.  I have 3 Eero Pro units.  I have several ports forwarded to internal devices and use a dynamic DNS service, and I rely on NAT loopback (I think also called hairpinning) so I only need to use the external dynamic hostname no matter where I am (inside or outside of my network).

Occasionally, from inside the network, I can no longer access those forwarded ports using the external hostname/IP.  From outside the network, it always works fine.  And yes, I'm sure that I'm using the correct external IP.

The strange thing is, the problem pops up and then disappears on its own.  Sometimes it only affects some forwarded ports and not all.  Sometimes the problem only occurs from one device on my internal network and works fine from another.

I had a Linksys Velop mesh wifi system and a few other routers before that which never had this issue.

Any ideas?

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  • This problem was more frequent before some of the firmware releases back in the late summer of 2018.  I RARELY have it happen any longer.  However, I access about 90 internal devices via host names that are resolved externally, and say 1 time out of a hundred I find the ports are blocked these days versus maybe 1 out of 10 in the past.  Rebooting the entire system corrects the issue, but like I said, the issue used to be far more common early last year.

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  • I'm having the same problem. It seems like every 3-4 weeks, it starts failing. I have to reboot the routers. I know rebooting the routers is not a huge deal. But it is an issue when other people are using the network. I have to wait until another time to do this. Are there any plans to look into this issue and address it once and for all?

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    • Thanks for reaching out schmatt and sorry to hear you're having some trouble here. We're not really aware of any ongoing problems, as such, with hairpin NAT, so this is definitely something we'd like to investigate with you in more detail. If you haven't already, please send an email with the details to support@eero.com and feel free to put "Community feedback" in the subject line and I'll make sure a senior specialist gets eyes on it! That goes double for you, arbies since you're the one who posted this thread! 

      We look forward to hearing from you so we can investigate your network setups and see what additional insights and improvements we can offer!

      Drew, eero Community Team

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