Okay found a solution though it is a little odd. I check the routing table and it returns the following:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 192.168.1.1 0.0.0.0 UG 0 0 0 wlan0
default 192.168.0.1 0.0.0.0 UG 0 0 0 enp0s17u1
192.168.0.0 * 255.255.255.0 U 0 0 0 enp0s17u1
192.168.0.1 * 255.255.255.255 UH 0 0 0 enp0s17u1
192.168.1.0 * 255.255.255.0 U 0 0 0 wlan0
192.168.2.0 * 255.255.255.0 U 0 0 0 usb0
So I remove the WLAN gateway manually route del default gw 192.168.1.1 and check if I can ping anything over the 192.168.0.1 gateway which didn’t work. So I run a nmap search on the 192.168.0.0/24 network address and it turn out that the lte modem stick has the IP 192.168.0.2. As soon I added that address as standard gateway (route add default gw 192.168.0.2 enp0s17u1) the connect work and I got a nice stream to my ntrip caster.
Any explanation for that?
ps: my routing table looks now like that:
# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.0.2 0.0.0.0 UG 0 0 0 enp0s17u1
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 enp0s17u1
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 enp0s17u1
192.168.0.1 0.0.0.0 255.255.255.255 UH 0 0 0 enp0s17u1
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 wlan0
192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 usb0
EDIT Actually it’s enough to just add the new route, it’s not necessary to remove the WLAN gateway, that was just for the testing purpose. I just wonder why a traceroute always start over the ip 192.168.0.1…