ISP Reports Problem with Open Portmapper - how do debug?

> Model: RBR50|Orbi AC3000 Tri-band WiFi Router

   Firmware version?  Connected to what?

> PORT: 111
> TAG: portmapper

   That's typically NFS-related.  I know nothing about Rogers policies
with respect to servers, but I suspect that (even if they allow it) you
don't want anything on your LAN exposed that way to the Internet.

> 1. Is there something in my NETGEAR Router Orbi setup I can check for
> port mapping?

   If someone in the outside world gets a response from your router at
port 111, which seems to be the case (as from here):

$ rpcinfo -p 99.238.182.129
   program vers proto   port
    100000    4   tcp    111  rpcbind
    100000    3   tcp    111  rpcbind
    100000    2   tcp    111  rpcbind
    100000    4   udp    111  rpcbind
    100000    3   udp    111  rpcbind
    100000    2   udp    111  rpcbind

then either the router itself is at fault, or it's passing such traffic
to/from some device on your LAN.  If we assume that the router itself is
too stupid to have such NFS functionality, then that would suggest one

of the following:
      UPnP
      DMZ
      Explicit port forwarding rules

   As a test, I'd disable all of those.  (See the User Manual for
details.)

> 2. When I use Google to get my public IP address, it's different than
> the one above - how can I tell if the router received a new public IP
> since 2021-04-25 06:32:47?

   Its current WAN/Internet IP address should be found at:
      ADVANCED > ADVANCED Home : Internet Port : Internet IP Address

   With my weak psychic powers, I can't see it, but you could plug that
address into the form at: https://whois.arin.net/ , and see if it is a
public or private address.

   As shown above, _something_ at "99.238.182.129" is responding at port
111.  ("telnet 99.238.182.129 111" also gets a connection.)  Whether
that's your RBR50, or something else of yours, or some other Rogers
customer is unknown to me.

> 4. rpcinfo -T -p <local IP address>

   Bad command syntax.  "man rpcinfo".  _Whose_ "<local IP address>" is
that?  The complaint from your ISP is about stuff on the WAN/Internet
side of your stuff, not anything on your LAN.

> 5. I have a Synology DS218 NAS connected via cable to the router for
> storing files; could that be doing something?

   It and a Mac would be plausible NFS users, but, if that activity
stays on your LAN, then your ISP should neither know nor care.

> 6. We use Apple iPads & iPhones - is anyone aware of something I
> should be checking on those?

   I doubt it.  A command like "rpcinfo -p localhost" on your Mac might
spew a bunch of stuff.  You could probe other, less likely devices by
specifying their LAN IP addresses.  But, again, this stuff is generally
harmless when confined to your LAN.  If it gets through your router to
the outside world, then you might expect complaints from your ISP.

"interfering with the Rogers network" is, I'd say, an exaggeration,
but running/exposing any server at all might violate their terms of
service for a residential account.

   Note that "port mapping" and "portmapper" are different from "port
forwarding".

      https://en.wikipedia.org/wiki/Portmap