Silly reverse proxy question

[Kandy]

I've been wondering, I run Jellyfin behind a reverse proxy, at jellyfin.mydomain.com. When I stream things inside my own home, is that traffic all being routed out through the internet, or is DNS smart enough to know it's local traffic and keep it on the local network?

Thanks

[TheDreadPirate]

Depends on your router.

Some routers automatically keep local traffic local. Some require you enable a setting or require you to setup a local DNS entry in the router that points to the LAN IP of my server.

Personally, I opt to have a local DNS entry in my router to ensure that my clients can still resolve my domain name when the Internet is out.

[jellynoob1994]

my shit standard isp router do's see local traffic
but millage may vary

[Boondocks1712]

I've been wondering, I run Jellyfin behind a reverse proxy, at jellyfin.mydomain.com. When I stream things inside my own home, is that traffic all being routed out through the internet, or is DNS smart enough to know it's local traffic and keep it on the local network?

It depends. If you have a split-horizon DNS and your internal clients resolve the internal IP address of your server when querying for jellyfin.mydomain.com, then your router is not going to see the traffic (assuming client and server are in the same VLAN).

If your internal clients resolve the public IP address of your router, then the traffic will go to the router and it will have to do what it's known as NAT loopback or NAT hairpin to send it back to your server.

[bjd223]

Use your internal IP address instead of the DNS name when you configure your local clients. If you want to use the DNS name for everywhere you need to do one of the following;

1.) Turn on/configure hairpin NAT in your router (if it supports it)
2.) Setup split-DNS with a zone/record for your public TLD with the record pointing to your internal IP address
3.) Use something like the HOSTS file (in windows for example) to override DNS resolution on each device

1 and 2 are the "right way to do it" with number 3 being more of a workaround. I would just use the local IP address so you know it is staying local.