Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Npcap 0.995 loopback adapter breaks multicast #1605

Open
R-Smith opened this issue May 22, 2019 · 1 comment

Comments

Projects
None yet
2 participants
@R-Smith
Copy link

commented May 22, 2019

Npcap 0.995 / Windows 10 1903
The Npcap loopback adapter is installed with the same route metric as my physical wired NIC. This breaks applications, such as IP cameras, that use multicast traffic. Windows is sending the traffic to the Npcap loopback adapter, so my real NIC never sees it. This can be fixed by disabling the Npcap loopback adapter or by manually specifying a route metric. The Npcap installer should be setting a much higher route metric.

Here is the (trimmed) output of route print on my machine:

C:\> route print
IPv4 Route Table
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0         10.0.55.1      10.0.55.90     25
        127.0.0.0        255.0.0.0         On-link         127.0.0.1    331
        127.0.0.1  255.255.255.255         On-link         127.0.0.1    331
  127.255.255.255  255.255.255.255         On-link         127.0.0.1    331
      169.254.0.0      255.255.0.0         On-link     169.254.81.18    281
    169.254.81.18  255.255.255.255         On-link     169.254.81.18    281
  169.254.255.255  255.255.255.255         On-link     169.254.81.18    281
      172.30.24.0    255.255.255.0         On-link        10.0.55.90    281
       10.0.55.90  255.255.255.255         On-link        10.0.55.90    281
      10.0.55.255  255.255.255.255         On-link        10.0.55.90    281
    192.168.217.0    255.255.255.0         On-link     192.168.217.1    291
    192.168.217.1  255.255.255.255         On-link     192.168.217.1    291
  192.168.217.255  255.255.255.255         On-link     192.168.217.1    291
    192.168.249.0    255.255.255.0         On-link     192.168.249.1    291
    192.168.249.1  255.255.255.255         On-link     192.168.249.1    291
  192.168.249.255  255.255.255.255         On-link     192.168.249.1    291
        224.0.0.0        240.0.0.0         On-link         127.0.0.1    331
        224.0.0.0        240.0.0.0         On-link     192.168.217.1    291
        224.0.0.0        240.0.0.0         On-link     192.168.249.1    291
        224.0.0.0        240.0.0.0         On-link        10.0.55.90    281
        224.0.0.0        240.0.0.0         On-link     169.254.81.18    281
  255.255.255.255  255.255.255.255         On-link         127.0.0.1    331
  255.255.255.255  255.255.255.255         On-link     192.168.217.1    291
  255.255.255.255  255.255.255.255         On-link     192.168.249.1    291
  255.255.255.255  255.255.255.255         On-link        10.0.55.90    281
  255.255.255.255  255.255.255.255         On-link     169.254.81.18    281
===========================================================================

Notice the lines for 224.0.0.0. Those are for multicast traffic. 10.0.55.90 is my physical wired NIC. 169.254.81.18 is the Npcap loopback adapter. They both have a metric of 281.

@gbdavidx

This comment has been minimized.

Copy link

commented Jun 3, 2019

it seems to break the outgoing interface alltogether on windows 10, 1803, i can ping outside, but can't browse anything, when i uninstall npcap internet will work normally

255.255.255.255 255.255.255.255 On-link 169.254.81.18 281

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.