Ignoring the most specific route?

Marian Hercek 236 Reputation points
2020-09-01T15:19:55.427+00:00

Server has two interfaces (192.168.101.19 with netmask 255.255.255.0 and 192.168.151.253 with netmask 255.255.255.0).
If I ping a client 192.168.126.14 from the server, packets go through default route (192.168.101.1).

Why?

Route to host 192.168.126.14 is the most specific and therefor it should be top priority.
Also route's metric is lower than default's route.

21934-image.png

Windows Server
Windows Server
A family of Microsoft server operating systems that support enterprise-level management, data storage, applications, and communications.
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  1. Marian Hercek 236 Reputation points
    2020-09-03T12:21:38.657+00:00

    Well, it's quite interesting how Windows works...

    The problem was at host level (running ESXi) where a Port Group was missing correct VLAN ID.

    So Windows was able to ping gateway but not able to pass packets through the gateway.
    Maybe Windows is able to detect that situation hence it was trying to push packets via different gateway.

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  1. Sunny Qi 10,656 Reputation points
    2020-09-02T07:43:06.747+00:00

    Hi,

    Thanks for posting here.

    Normally, if the specific route entry to a host was added and the metric was smaller than the default, then the route to this host should be go through the specific route.

    Please try to delete the specific route entry and then add this entry again to see if the issue was resolved. If the issue is still existed, please help to provide screenshot of the error message for us further troubleshooting.

    I have tested in my lab and here is the result for your reference.

    A server with 2 NICs:
    NIC A: 192.168.0.1 255.255.255.0
    NIC B: 192.168.2.1 255.255.255.0

    Route print result of this server:

    22120-image-4.jpg

    Then ping host 192.168.126.14, the gateway 192.168.0.1 responded

    22167-image-1.jpg

    Add a specific route entry of host 192.168.126.14 to go through gateway 192.168.2.1

    22108-image-2.jpg

    Then ping 192.168.126.14, the gateway 192.168.2.1 responded

    22058-image-3.jpg

    Hope my answer will help you!

    ---Please Accept as answer if the reply is helpful---

    Best Regards,
    Sunny

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