Comment by styanax | Hacker News Reader

Comment by styanax | Hacker News Reader

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I'm sure geo has something to do with it - my connections generally terminate in Austin, TX but it varies around Central US. I have T-Mobile Home Internet and our IPs show up to remotes under the same general ASNs as the traditional mobile network (big huge CGNAT, my IP can change 5 times a day or whatnot and it doesn't reflect where I actually am located).

Edit: in case useful to someone reading, right now I have an IP assigned out of this block:

    NetRange:       172.32.0.0 - 172.63.255.255
    CIDR:           172.32.0.0/11
    NetName:        TMO9
    NetHandle:      NET-172-32-0-0-1

Edit edit: in the network record is a link to the self-reported geo data, I missed that.

    Comment:        Geofeed https://raw.githubusercontent.com/tmobile/tmus-geofeed/main/tmus-geo-ip.txt

If you're behind a big CGNAT and Google knows it, they might intentionally return multiple addresses to have more capacity.

Each service port (IP:Port) can only receive 64k connections from each NAT IP, returning more IPs from DNS makes more connections available. Google is a very popular service, so it makes sense to do. (Less so for v6, though)

Alternately, if they can't get a good feel for where you are, returning A records for multiple locations makes sense, too.

No idea why 4 AAAA vs 6 A; Google runs dual stacked and I'd expect the same number of records for both; IIRC, 8 AAAA will usually fit in a 512 byte udp reply, and anyway DNS64 might expand As into AAAAs, so you have to gauge sizes with those anyway.

> Each service port (IP:Port) can only receive 64k connections from each NAT IP

Interestingly, for Tor, the lowest common denominator local port exhaustion threshold at exit is 16384.

https://spec.torproject.org/proposals/348-udp-app-support.ht...

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