DNS rebinding Plex pihole DHCP

[mrdrew]

Plex downloads fail when away from home. Plex for iphone.

pihole is the DHCP server and only DNS for the home network. It's running on a raspberry pi dedicated to this job. I have an Orbi 750 and single satellite doing wifi over my home. Orbi WAN has addressable external IP on the WAN, Centurylink modem is in bridge mode.

Here's the most authoritative answer I've received over at the [Plex forums] (Plex iOS fails downloading, pihole at home - #4 by OttoKerner - Remote Access - Plex Forum)
"You need to tell the pi-hole that it shall not block DNS rebindings on the plex.direct domain."

But everywhere I look, the DNS Rebinding is found in the router (dd-wrt, Netgear, or pfSense, etc.) I'm just not sure where this setting should go: in the pihole server interface via GUI or .conf file somewhere, or if it must be on my router (which is cheap and doesn't give me access to something like DNS Rebinding).

[jfb]

I will note that I have a PLEX and Pi-hole, and no problems streaming content away from home.

The only plex.direct domain queries I get are the typical

IP-followed by all the letters of the alphabet-followed by 0-5.plex.direct.com

Example:

query[A] 192-168-0-113.abcdefghijklmnopqrstuvwxyz012345.plex.direct from 192.168.0.113

These are forwarded to my upstream resolver (unbound) and resolve to nothing. But the PLEX still appears to work normally.

On your router have you forwarded the PLEX port? Here is what is in my router:

[mrdrew]

I can stream away from home, but cannot download for offline: Those download attempts fail.
I see no "plex" anything in my pihole query log.
I have forwarded ports 32400 on the Orbi router, Plex reports all green checks for connections.
I'm 99% I do NOT have Unbound installed, and am only on default pihole settings. I did monkey around with setting up Unbound last year, but it stopped working and I wiped the SD card and started over w/out Unbound.

[Bucking_Horn]

@mrdrew

I see no "plex" anything in my pihole query log.

If Pi-hole would not receive any related *.plex.direct queries, that would suggest that Pi-hole would not be involved.

In the linked post over at the Plex forum, you state that "Download for offline stopped working".
Does that mean it has worked before with Pi-hole? What has changed?

EDIT:
Also, you mention that you encounter failures "at the end of the download" and that "Plex on iOS still fails".

For the former, if Pi-hole would be involved, it would be likely that the download would never have started, since the client needs to successfully resolve a domain to download from prior to downloading.
For the latter, does that mean that downloads succeed from clients other than iOS?

Both observations would again suggest that your issue may be with your client rather than Pi-hole.

[mrdrew]

All excellent points. I will head over to plex forums and see what I can find over there. Thank you very much!