Some port filtered from client



  • Hi,

    I access via openvpn to my virtual server (proxmox) and I have a very special problem:

    -Connected through the VPN I can access two Windows guest with RDP, if I nmap the machine the open port appears open. (work as expected)
    -Connected through the VPN I cannot access the Linux guests with SSH, if I nmap the machine the open port appears filtered (even the port 80) but the guests answer to my ping requests.
    -Connected through a ssh tunnel I can access everything, the open ports appears at open and everything works fine.

    The guest are on the same network. I have some other install with the same settings and everything work well. We really do not understand.

    Help please.



  • Replying to myself, I found the solution thanks to this post: https://forum.pfsense.org/index.php?topic=88467.msg504596#msg504596

    Go to "System->Advance Networking" and disable:

    • Hardware Checksum Offloading
    • Hardware TCP Segmentation Offloading
    • Hardware Large Receive Offloading

    and reboot.