Slow speeds while in DMZ+ mode

I'm on the phone with AT&T fiber right now.  The tech is telling me "we don't support DMZ mode, and we can't ship you a new gateway unless there's a problem with one of the features we do support"

Ideas?

whoops, double post.

About all you can do is buy a GW off ebay or roll back you firmware. I opted for the rollback a few months ago and all has been well.

How long ago was it that you had the service hooked up? I just called the actual technician that came out and installed it and he came back a couple days later and swapped it for a different model that had pass through option (BGW210). I wouldn't bother with calling or chatting with AT&t. 

I was going to re-iterate that as well.  Do NOT call. Your just getting CSRs that likely have no idea of the issue.

You might have luck with the chat option selecting the Technical Issue, I did.  It was painless for me. I provided the links, etc., and got someone who understood the issue.  I had the new GW in a few days.  I did however have to go back and insist on getting the bill credits for the gateway as they started charging me the monthly fee for it, citing the need for the new GW was due to ATT's firmware issue, which they honored.

But barring that, call the actual technician that installed it if you have their number.

Service was installed a couple of months ago.  Customer retention was able to get them to attempt to ship me a BGW210, but when they checked the warehouse, there were none in stock.  I guess that's better than putting the order in and them just shipping me another 5268.  They offered to send a tech who should have on on the truck.  That tech will be here this afternoon, fingers crossed that they'll have a BGW210 or at least a non-5286 gateway.

Found this as well, in response to the CSR's claim that they don't support DMZ:

https://www.att.com/esupport/article.html#!/smb-internet/KM1188700?gsi=1n7s6l

I just received new service today and spent forever trying to figure out the issue-- luckily this forum showed up on google rather quickly.  

Correction: My 5268AC shipped with the 11 firmware but I was unable to downgrade it using the instructions offered by "y0bailey" on the other discussion here-- https://forums.att.com/t5/AT-T-Fiber-Equipment/PACE-11-1-0-531418-DMZ-Issue/m-p/5745153#M7940

I tried a combo of upgrades followed by hard resets (with lots of red blinking lights).  I suppose I will either be arguing to cancel service or buying a different modem/gatway on eBay.

FYI, in that forum AT&T offers a "workaround" which isn't an actual fix for many reasons, you router won't know its real external IP address which will break a lot of things... P2P VPN tunnels, VoIP sessions, and basically anything using uPnP (facetime, Skype, wemo, nest, etc).  

So it seems according to this post:

https://forums.att.com/conversations/att-fiber-equipment/speed-issues-with-pace-5268ac-dmz-mode/5df007f7bad5f2f606ac6c66?page=1

That this has been fixed with a firmware update??

And this is no longer an issue then??