> I have a D6400 DSL Modem in modem mode (not using as router). [...]
What does "modem mode" mean to you? ADVANCED > Advanced Setup >
Device Mode : Modem (Modem only), or something else?
As usual, showing actual actions (commands) with their actual results
(error messages, LED indicators, ...) can be more helpful than vague
descriptions or interpretations ("in modem mode").
> [...] also one cable from lan port on modem to gb switch.
Sounds wrong to me. If the D6400 is actually configured as a modem
only, then I'd connect exactly one device to it: your "my TP Link Archer
C9 router internet port".
> IMG_1001.jpg
No, no, no. You're connecting the D6400 LAN to the Archer C9 LAN
(through the switch). This stuff is not Christmas-tree lights, and you
can't even connect Christmas-tree lights in a circle.
> 1. Do I need any routes set for my router to use the lan ports on the
> D6400?
Not if it's configured as a modem only.
> 2. If I disconnect the wire from D6400 to the gb switch it appears my
> wifi clients can connect to the router wifi but have nor internet.
_Which_ "the router wifi"? "the router wifi" on the D6400, or "the
router wifi" on the "my TP Link Archer C9 router internet port", or
what?
If the D6400 is actually configured as a modem only, then it should
not be offering wireless service.
> Any thoughts or better ways to connect the D6400 to the the clients
> can connect constantly & not intermittenly?
Does that mean that you're having some actual problem? As usual, you
might get better advice if you described the actual problem which you
are trying to solve, rather than asking how to implement some particular
"solution" ("any routes") which may have little or nothing to do with
your actual problem.
If you connected this stuff as shown in your picture, then I'm a
little amazed that you got even intermittent operation.
You seem to have DSL service of some kind, and you're relying on the
D6400 for that. What's the purpose of the Archer C9? Extend the
wireless-network coverage of the D6400, or be the only router, or what?
If "Extend", then you might want to configure the D6400 in its
default mode, "Router (Modem + Router)", and then configure the Archer
C9 as a wireless access point. See the Archer C9 documentation for how
to do that.
If you want the Archer C9 to be the only router, then you should
_really_ configure the D6400 as a modem-only, and connect only the
Archer C9 to it.
The current topology of this stuff shown in your picture is clearly
goofy. What's the geograpy of this stuff? Is it all in one place, or
are some of the pieces separated from others, or what?
Lets start again. What, exactly, are you trying to do with all this
stuff?
