False positive? Port TCP:0 Open

GVM versions

gsad 21.4.3
gvdm 21.4.4
OpenVAS 21.4.3
gvm-libs 21.4.3


Ubuntu 20.04.3

Hi, I am new here. We are testing with Greenbone and it looks nice and works good so far.

We see the “Port TCP:0 Open” result on multiple hosts but i cannot find a solution for this and did no see this before. Can anyone help? Is this a false positive? It looks like an old NVT and there is not much info on this.


Hi @Jurn and welcome to the forum :slight_smile:

I searched and didn’t see an answer, but I’m bumping this to see if anyone has ideas.

Hello DeeAnn,

thank you. I’ve found the issue already, it wasn’t a false positive there was a problem with the firewall. For anyone who would like to know. This was related to syn flood detection, this was enabled on the NSX Edge firewall in vmware. This results in all ports open (and I mean all). The scanner was correct. Only nothing was running on that port or others. We managed to solve this by disabling syn flood detection.

Regards Raymond


Hi @Jurn,

I’m glad you were able to find the problem and thank you for sharing the solution. :slight_smile:

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