pfSense

Maybe a bug, I don't know - found a solution too...

Hardware for pfsense (since 2.2.x):
Intel Celeron J1900 with 4 Intel Pro/1000 NICs, 8GB RAM, 32GB SSD

NIC-Configuration:
em0 = WAN
em1 = LAN
em2 = unused
em3 = unused

Both interfaces are on the same switch (Netgear GS-724Tv4) and configured with VLANs - as followed:
LAN:
VLAN 1, VLAN 6, VLAN 10 configured as tagged VLAN on the port in the switch (Netgear) and as VLAN configured in pfsense -> the interfaces are em1.1, em1.6 and em1.10

The internal port LAN in pfsense has 3 networks: LAN, DMZ and TESTLAN.

WAN:
VLAN 4, but configured in the switch (Netgear) as untagged VLAN.

The external port WAN in pfsense is only em0.

Everything worked fine until Version 2.4.3 (with a lot of packages), but what is happened in 2.4.4 - without packages, only pure 2.4.4 (upgrade and full install from USB-Image):
The WAN-interface begins to auto-negotiate with the switch every few seconds (between 3 to 5 seconds) and the pfsense WebGUI is absolutely unresponsive and a SSH-Session with putty stops after the login with a black screen. You can only use the console connected directly to the pfsense. The internet-connection is absolutely unuseable.

After a lot of hours (days) sitting and testing I found a solution (maybe a solution - I don't know):

When I also configure the WAN-Port in pfsense and the switch (Netgear) as a tagged VLAN, everything works fine!
But I think that means, that I can't connect a cable- or dsl-modem (or something else for a internet-connection) which haven't the capability to configure VLANs. I must use a switch with tagged VLAN between WAN in pfsense and the NIC of the internet-device (modem, router, etc.). Or I must use a switch on LAN which has the capability of VLAN-routing.

As I said: I don't know if this is a bug or not, maybe it is (or was) a wrong configured WAN port in the older versions of pfsense (<=2.4.4). Or it is a problem of the Intel PRO/1000 Nics in FreeBSD 11.2-RELEASEE-p3, which is used in pfsense 2.4.4 and weren't a problem in older versions of FreeBSD, which were used in older versions of pfsense.