@IrvSp 

Based on this it looks to a issue with the route the data was taking.  Before you put the computer in a DMZ and reset the adapter the route the router chose for the data took you to a Specturm owned backbone address at which point the traffic was firewalled and caused the operation to fail.  As I am sure you know each time a computer is connected to a different source the route can change as that is chosen by the router or modem if its dirrectly connected.  Probably why the older routers were working is because they chose different routes.  It also appears when you placed the computer in the DMZ and reset the adapter that the route changed.  One last test if you don't mind.  run the trace again now that the PC is not in the DMZ.  See if this fixed the route issue. 

Thank you.

P.S.  I sent your trace routes to Parker  

@Carl,

Yes, I do know that even 2 successive tries with the same command can be different, even without an IP Address change. What is of note is that the first attempt going through the router resulted in a timeout (over 30 hops and I see I posted that twice, sorry). I'm talking about the MAIL.BRIGHTHOUSE.COM, not MAIL.TWC.COM. Now when I put the PC into the DMZ, the IP Address it appears to the outside world is still the WAN IP Address of the router. The PC's is 192.168.0.20.

Now since in both cases, the PC is going out via the router, I would expect the same end result, that is 30 hops and a timeout. DMZ does nothing more that put the router beyond any internal blocks on the router, that is it has all UDP and TCP ports open and exposed. To the WAN, it has the SAME IP Address assigned to the router, so one would expect the same results, that is timeout on the 30th count, but when on the DMZ, a different result happened. It ended on the 14th hop, "  14     *        *     184-088-029-070.res.spectrum.com [184.88.29.70]  reports: Destination host unreachable. "

This would be a Router issue possibly as it handles packets going out via 'normal' differently than when on the DMZ.

Thanks for sending it one, but I did also send it to Parker.

@IrvSp 

Sorry about that i mis-read the DMZ traceroute.  I thought it actually showed it was successful. Yeah defiently something we need to look at.  

@Carl ,

Just got the e-mail from Parker and he CC:'ed you. I responded back but didn't do 'ALL', so you didn't see my response.

No problem anyway. Nice to know that TRACERT didn't mean anything, but Parker is still working on this.

Thank you again.

@Carl,

Parker was on again last night (Great Tech Support person by the way). We determined what the root problem is/was. My ISP it seems. Yes, it appears my WAN IP Address when the A20 is connected to the modem and all devices connected to the A20 can use the SMTP server MAIL.BRIGHTHOUSE.COM. It returns an error that it isn't available.

My RT-N56U works fine with the same SMTP server, as does my PC directly connected to the modem.

Parker tried all 3, A20, RT-N56U, and PC direct to the modem, and when the A20 was connected did it fail. He captured all packets and they looked the same?

So he CLONED my PC MAC to the A20 and it works fine.

Conclusion, the ISP has blocked the SPECIFIC IP Address the A20 is assigned. Cloning makes the A20 appear as my PC and it gets the IP Address assigned to my PC.

Sooooo... this morning I called my ISP, but before I did that, I scoured my wife's PC with MalwareAntibytes and Spybot Search and Destroy to make sure she wasn't seening out SPAM unknown to her as whe was infected. Her PC is clean. Was even told if she was actually sending Spam out and they caught it her ID would be suspended and she's get a different error and couldn't even get her e-mail, which she could.

Tried explaining that the IP Address is blocked by the SMTP server... and it took about 10 minutes to convince the agent that was the case. Was always told call Outlook Support or MS.... finally insisted to talking to a Supervisor or level 2 or 3. Only then did she transfer me to Charter Network Support. Another 10 minutes of 'call Outlook or MS' before I finally got through it is a SPECIFIC IP Address only that causes the problems. Asked if the agent could assign a NEW IP Address to the router and was told NO, they do not have that capability. Only way to do that, REPLACE the MODEM... Took 45 minutes to reach that conclusion.

So for now, I'll stay CLONED, but if I notice problems, I will.

All this info I'm posting so if others think they have the same problem they'd know the answer I got.