Android 9 "Private DNS"/"DNS over TLS" IPv6 link local to unbound port 853 spam



  • I am seeing port 853 from my android 9 device with default setting of private dns enabled trying to connect to the pfsense unbound dns server ipv6 address getting blocked. The source is link local address.

    I am not sure if I should block this or allow it. Any ideas?

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  • LAYER 8 Global Moderator

    If your going to run dns on IPv6, then yeah you should not be blocking IPv6 ;)


  • Rebel Alliance Developer Netgate

    That's up to you. If you have IPv6 enabled on the LAN, and that really is trying to hit the LAN IPv6 address of your firewall, and you have Unbound set to act as a DNS over TLS server, then you probably want to pass them.

    If it's going to some other DNS server you probably still want to allow them.



  • @jimp yes I have dns over tls enabled in unbound.
    I guess it will help with anyone sniffing packets on my lan.
    Thanks for help, I just created a rule to allow it.


  • LAYER 8 Global Moderator

    And who is on your lan? And you have old time hubs? Or wifi?

    Hmmm - let me think...
    I run a service on port X that I want my clients to use.. Should I allow access to this port or not from the clients on my network.. Yah Yah -- I could see why you should check on that ;)



  • @johnpoz i am on my lan lol. I have a network tap doing full packet capture and analysis using security onion between my main switch and pfsense.


  • LAYER 8 Global Moderator

    So you want to prevent yourself from sniffing your own traffic?

    So your protecting yourself from yourself.. So yeah lets make dns lookups slower and use more overhead.. Sounds like a fantastic plan <rolleyes>



  • @johnpoz 3.8 seconds at the worst. its around 1 sec without dns over tls. I can live with that.
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    edit: i am going to add cake traffic shaping in front of pfsense soon so that number will improve.
    edit2: and I am very self aware of turning on knobs even if it makes no sense. lol


  • LAYER 8 Global Moderator

    For what reason are you wanting to wrap overhead around your query when its on your own lan? If the network is not hostile why and the F would you want to add overhead to the query be it 1 ms even. Makes zero sense.. Zero!!!

    Have fun... Just utterly pointless.. LIke putting a lock on your thermostat to prevent change - when the only one in the house is you..



  • @johnpoz yes you are right. I am a idiot for doing this and I am well medicated with my illogical paranoid self.


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