i can do SSH in linux via NCM interface, please see below:
//Here I set the NCM interface in linux PC to be 192.168.1.2
owner@ubuntu:~$ sudo ifconfig usb1 192.168.1.2
owner@ubuntu:~$ ifconfig usb1
usb1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.2 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::3422:2dff:fe6c:52c9 prefixlen 64 scopeid 0x20<link>
ether 36:22:2d:6c:52:c9 txqueuelen 1000 (Ethernet)
RX packets 81 bytes 9062 (9.0 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 367 bytes 54939 (54.9 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
//In UART2 console or ECM interface, config the WP76 module's NCM interface to have IP address 192.168.1.1
root@swi-mdm9x28-wp:~# ifconfig ncm0 192.168.1.1
//now ssh from PC to module's NCM interface
owner@ubuntu:~$ ping 192.168.1.1 -I usb1
PING 192.168.1.1 (192.168.1.1) from 192.168.1.2 usb1: 56(84) bytes of data.
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=5.62 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=4.15 ms
64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=2.77 ms
^C
--- 192.168.1.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2003ms
rtt min/avg/max/mdev = 2.777/4.188/5.629/1.165 ms
owner@ubuntu:~$ ssh root@192.168.1.1
root@swi-mdm9x28-wp:~# ifconfig ncm0
ncm0 Link encap:Ethernet HWaddr DE:6E:E7:CC:C0:23
inet addr:192.168.1.1 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::dc6e:e7ff:fecc:c023/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:463 errors:10 dropped:0 overruns:0 frame:0
TX packets:162 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:59233 (57.8 KiB) TX bytes:25548 (24.9 KiB)