Wired connections constantly drop with Fios Gigabit

[Muftobration]

I have had severe connection issues since upgrading to Fios Gigabit service with a Verizon-supplied CR1000A router last year. Previously I had 100/100mbit Fios service with my own Linksys router and everything was fine.

The issue is only present when on a wired connection. I tested on a laptop with an ethernet jack via wired and wireless and see the issues only when wired. My wired desktop always suffers. My work laptop on WiFi is always fine. Using different ethernet jacks on the router does not help.

The issue is that webpages randomly stop loading. For example, I might be able to load a video on youtube, only for the comments to fail to load and the video to stop buffering half-way through. My gmail inbox almost never loads. If it does load, when I try to click on an email I get the yellow "reconnecting..." banner at the top with a timeout. I have rarely been able to read an email on a wired connection since switching to this service. Other websites are hit or miss. It's a roll of the dice every time I click a link. Speedtest.net (if I can get the page to load) and Verizon's own speed test tool show no issues with bandwidth or ping.

I spent over two hours on the phone with support months ago trying to resolve this issue and the agent eventually put in a request for me to replace my router. The replacement router has exactly the same problem.

How can I troubleshoot this further?

[Cang_Household · Accepted solution]

I would consider the wired network cards , whether they are made by Intel.

Years ago, Intel has issued a memorandum regarding IPv6 incompatibility between certain ONTs and their wired Ethernet interface cards.

Any Intel Ethernet cards listed below may suffer from this incompatibility, which I roughly estimate to be 70-80% of consumer electronics.

Intel® 82583V Gigabit Ethernet Controller
Intel® 82579LM Gigabit Ethernet PHY
Intel® 82579V Gigabit Ethernet PHY
Intel® Ethernet Connection I217-LM
Intel® Ethernet Connection I218-LM
Intel® Ethernet Connection I218-V
Intel® Ethernet Connection I219-LM
Intel® Ethernet Connection I219-V
Intel® Ethernet Server Adapter I210-T1
Intel® Ethernet Converged Network Adapter X540-T2
Intel® Ethernet Converged Network Adapter X540-T1
Intel® Ethernet Controller X540-AT2
Intel® Ethernet Converged Network Adapter X520-DA1
Intel® Ethernet Converged Network Adapter X550-T1
Intel® 82574IT Gigabit Ethernet Controller
Intel® Ethernet Controller I350-AM2
Intel® Ethernet Controller I350-BT2
Intel® Ethernet Controller I350-AM4
Intel® Ethernet Controller X540-BT2
Intel® 82541GI Gigabit Ethernet Controller
Intel® 82545EM Gigabit Ethernet Controller
Intel® 82567LM Gigabit Ethernet Phy
Intel® Ethernet Connection I217-V
Intel® Ethernet Server Adapter X520-DA1 for Open Compute Project
Intel® Ethernet Server Adapter X520-DA2 for Open Compute Project
Intel® Ethernet Converged Network Adapter X710-DA4
Intel® Ethernet Controller X550-AT2
Intel® Ethernet Controller X550-BT2
Intel® Ethernet Converged Network Adapter X710-T4
Intel® Ethernet Server Adapter I350-F2
Intel® Ethernet Server Adapter I350-T4V2
Intel® Ethernet Converged Network Adapter X710-DA2
Intel® Ethernet Converged Network Adapter X550-T2
Intel® Ethernet Connection X557-AT2
Intel® Ethernet Connection X557-AT4
Intel® Ethernet Converged Network Adapter X520-SR2
Intel® Ethernet Converged Network Adapter X520-DA2
Intel® Ethernet Converged Network Adapter X520-LR1
Intel® Ethernet Converged Network Adapter X520-T2
Intel® Ethernet Controller I210-AS
Intel® Ethernet Controller I210-IS
Intel® 82580EB Gigabit Ethernet Controller
Intel® 82598EB 10 Gigabit Ethernet Controller
Intel® Ethernet Controller I210-AT
Intel® Ethernet Server Adapter I350-T2V2
Intel® Ethernet Server Adapter X710-DA2 for OCP
Intel® Ethernet Controller X550-AT
Intel® 82599EN 10 Gigabit Ethernet Controller
Intel® Gigabit CT Desktop Adapter
Intel® 82578DC Gigabit Ethernet PHY
Intel® PRO 1000 PT Dual Port Server Adapter
Intel® 82566MM Gigabit Ethernet PHY
Intel® 82576NS Gigabit Ethernet Controller
Intel® 82577LC Gigabit Ethernet PHY
Intel® 82566MC Gigabit Ethernet PHY
Intel® 82599ES 10 Gigabit Ethernet Controller
Intel® Ethernet Converged Network Adapter X520-QDA1
Intel® 82574L Gigabit Ethernet Controller
Intel® Ethernet Server Adapter I350-F4
Intel® Ethernet Controller I210-IT
Intel® 82572EI Gigabit Ethernet Controller
Intel® 82571EB Gigabit Ethernet Controller
Intel® 82599EB 10 Gigabit Ethernet Controller
Intel® Ethernet Controller I210-CS
Intel® Ethernet Converged Network Adapter X520-SR1
Intel® PRO 1000 PT Quad Port Low Profile Server Adapter
Intel® 82578DM Gigabit Ethernet PHY
Intel® 82573L Gigabit Ethernet Controller
Intel® PRO 1000 PT Quad Port Server Adapter
Intel® 82573E Gigabit Ethernet Controller
Intel® 82566DM Gigabit Ethernet PHY
Intel® 82577LM Gigabit Ethernet PHY
Intel® 82566DC Gigabit Ethernet PHY
Intel® Ethernet Server Adapter X520-DA2
Intel® 82575EB Gigabit Ethernet Controller
Intel® 82576EB Gigabit Ethernet Controller
Intel® 82573V Gigabit Ethernet Controller
Intel® 82540EP Gigabit Ethernet Controller
Intel® 82544GC Gigabit Ethernet Controller
Intel® 82543GC Gigabit Ethernet Controller
Intel® PRO 1000 MF Server Adapter
Intel® 82563EB Gigabit Ethernet PHY
Intel® 82544EI Gigabit Ethernet Controller
Intel® 82564EB Gigabit Ethernet PHY
Intel® PRO 1000 MF Server Adapter (LX)
Intel® 82545GM Gigabit Ethernet Controller
Intel® 82541PI Gigabit Ethernet Controller
Intel® 82546EB Gigabit Ethernet Controller
Intel® 82546GB Gigabit Ethernet Controller
Intel® 82540EM Gigabit Ethernet Controller
Intel® PRO 1000 MF Dual Port Server Adapter
Intel® Ethernet Controller I211-AT
Intel® 82580DB Gigabit Ethernet Controller
Intel® 82597EX 10 Gigabit Ethernet Controller
Intel® 82541ER Gigabit Ethernet Controller
Intel® 82547GI Gigabit Ethernet Controller
Intel® Ethernet Connection X557-AT
Intel® Ethernet Network Connection I347-AT4
Intel® 82567V Gigabit Ethernet Phy

https://www.intel.com/content/www/us/en/download/19174/disabling-tcp-ipv6-checksum-offload-capabilit... As suggested by their website, disabling the IPv6 TCP Checksum Offload may help; however, this remedy is largely insufficient given Google websites, such as YonTube, have started using QUIC over UDP as opposed to TLS over TCP. Given this, you also need to disable the IPv6 UDP Checksum Offload.

[Muftobration]

My desktop does indeed have one of those controllers (Intel® Ethernet Connection I219-V). I followed the steps at the link you posted for both TCP and UDP. After a quick 10-minute stress test (mainly YouTube and email) I have not experienced any dropouts.

Thank you so much for giving me this lead! I'll report back in a week to say whether it appears to be permanently resolved.