MX68 + ATT troubleshooting

[Fungible]

Hey there, we have 4 locations, two of which have ATT as the ISP. Those two ATT locations tend to regularly have issues with speed on specific websites/applications. Sometimes certain applications do not work at all and require a sitewide network reboot. The slow websites (including our company website) are consistent and only occur on those networks. ATT gateways are in passthrough mode. Are there any known issues that could be causing this? Both ATT/MX68 locations experience the same issues at the same time.

[RWelch]

Have you checked the MTU?

Troubleshooting MTU Issues 

What MX firmware version are the MX68s currently running?

[cmr]

@Fungible I would try to get an evaluation of Meraki insight, or Cisco Thousand Eyes as to me it looks like the issue is with the ISP/telco due to both sites being affected at the same time.  However we both know that they will not accept that with more evidence...

[PhilipDAth]

To add to other answers; issues I have run into relate to using the wrong DNS servers, causing sub-optimal content distribution servers being used.

Make sure you are using DNS servers appropriate for the ISP connection you are using.

To diagnose this further, I would use Chrome Developer Tools and the waterfall graph to determine exactly what is causing the slowdown.  Is it the DNS response, the TCP setup, the TLS negotiation, the data transfer rate, or the coding of the website?

https://stackoverflow.com/questions/42605476/how-to-use-networks-waterfall-in-chrome-dev-tool-to-dia...

I'm assuming this isn't a WiFi or local access issue ...

[BHC_RESORTS]

There's also a million different types of ATT connections. Business DIA or MIS? Consumer fiber? DSL? Quasi-business non-dedicated fiber? Direct or through one of their internal resellers?