What's causing crazy netstat output?

[mauricev]

Two machines identically configured. On one, netstat returns

tcp        0      0 127.0.0.1:9000          0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:3306          0.0.0.0:*               LISTEN     
tcp        0      0 45.76.6.231:497         0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:497           0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
tcp6       0      0 :::33060                :::*                    LISTEN     
tcp6       0      0 :::80                   :::*                    LISTEN     
tcp6       0      0 :::22                   :::*                    LISTEN     
tcp6       0      0 :::443                  :::*                    LISTEN

On the other, 

tcp        0      0 localhost:mysql         0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:ssh             0.0.0.0:*               LISTEN     
tcp        0      0 localhost:9000          0.0.0.0:*               LISTEN     

Why is Apache showing up in one and not the other? More generally, why does one list IPv6 connectivity and the other not?

[palica]

probably missing ipv6 connectivity on the second one

[mauricev]

How can a machine be missing ipv6? Also, they're identical.

[mauricev]

I figured it out. One is a slightly older build than the other. The debian-kernal lts had to have been compiled against different configs.

The one with ipv6 is running 4.9.168_p1 and the one without 4.19.37_p6. I guess this is a bug. ipv6 was left out of the newer kernel.

[mauricev]

https://bugs.funtoo.org/browse/FL-6605

[mauricev]

Can confirm that the kernel has IPv6. The bug is elsewhere.

[mauricev]

What I am noticing is that on the machines with ipv6, the nf_conntrack modules are loaded.