Sysinternals
Advanced system utilities to manage, troubleshoot, and diagnose Windows and Linux systems and applications.
1,243 questions
Bug Report: tcpview bad IPv6 name resolution
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James Garrison
246
Reputation points
TCPView v4.19 on Windows 11
With "Resolve names" OFF, tcpview displays the local and remote IPv6 addresses.
With "Resolve names" ON, it produces spurious "names" that look like IPv4 addresses, and then attempts to resolve those where possible.
Sysinternals
{count} votes
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![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(80, 60%, 17%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EJM%3C/text%3E%3C/svg%3E)
Jason McCord 0 Reputation points2024-10-08T17:16:14.0166667+00:00 The "Resolved Address" appears to be the first parts of the IPv6 address converted to decimal and formatted as an IPv4 address.
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![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(284.8, 12%, 37%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EMS%3C/text%3E%3C/svg%3E)
Matthew Steeples 106 Reputation points2024-10-14T13:53:39.7866667+00:00 I'm seeing this with Resolve Names on too. It's gone one step further and taken the first part of the IPv6 address converted to decimal and formatted as an IPv4 address and then done a DNS lookup on that. Those "fibrefirst" records are actually 2603:1020:5:4::f (somewhere in Azure)
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