Why IPv6 Causes TCP Timeout Errors in Chrome on Windows 11
Windows 11 enables IPv6 by default, and many websites and CDN services still primarily use IPv4. When Chrome attempts to connect to a domain that has both A (IPv4) and AAAA (IPv6) records in DNS, Chrome prefers IPv6 by default. If the website’s IPv6 address is not routable from the user’s network (common on ISP networks that do not have IPv6 peering agreements), the TCP handshake times out over IPv6 before Chrome falls back to IPv4.
The timeout occurs because Windows 11’s IP stack attempts the IPv6 connection first and waits for the full TCP timeout before attempting IPv4. The default IPv6 connection timeout is often longer than the IPv4 timeout, causing the overall connection attempt to take significantly longer before failing.
Resolving IPv6-Induced TCP Timeouts
Disabling IPv6 on Windows 11
Open Control Panel → Network and Sharing Center → Change adapter settings. Right-click your active network adapter → Properties. Uncheck Internet Protocol Version 6 (TCP/IPv6). Click OK and restart the PC. This forces Windows 11 to use only IPv4 for all connections, eliminating IPv6 routing failures as a cause of timeout errors.
Disabling IPv6 in Chrome Only
If you do not want to disable IPv6 system-wide, download Chrome with the following command-line flag added to the shortcut:
--disable-ipv6
Launch Chrome with this flag — Chrome will only attempt IPv4 connections, bypassing IPv6 routing issues while leaving the system IPv6 configuration intact.
Flushing IPv6 DNS Cache
Open Command Prompt as Administrator and run:
ipconfig /flushdns && ipconfig /6flushdns
This clears both the IPv4 and IPv6 DNS caches, forcing Windows 11 to perform fresh DNS queries for both protocol versions. If stale AAAA records are causing Chrome to connect to unreachable IPv6 addresses, this flush resolves the issue.
Call to Action
Use the webs.ninja gateway to test whether IPv6 is the source of the timeout by running the TCP handshake latency monitor with IPv6 disabled (using the Chrome flag --disable-ipv6). If the diagnostic shows successful handshakes with IPv6 disabled, apply the IPv6 disable or flush fixes above.