我的虚拟机里有两块网卡，虚拟机的操作系统是18.04。
01-network-manager-all.yaml 的内容为：
it@it51:~$ cat /etc/netplan/01-network-manager-all.yaml
# Let NetworkManager manage all devices on this system
network:
version: 2
renderer: networkd
ethernets:
enp3s0:
dhcp4: true
addresses: []
optional: true
enp0s31f6:
dhcp4: no
addresses: [172.16.11.39/23]
gateway4: 172.16.10.1
nameservers:
addresses: [8.8.8.8]
enp3s0网卡的ip是172.16.10.120
it@it51:~$ ifconfig
enp0s31f6: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.16.11.39 netmask 255.255.254.0 broadcast 172.16.11.255
inet6 fe80::c600:adff:fe38:7cc8 prefixlen 64 scopeid 0x20<link>
ether c4:00:ad:38:7c:c8 txqueuelen 1000 (Ethernet)
RX packets 649361 bytes 148866878 (148.8 MB)
RX errors 0 dropped 284603 overruns 0 frame 0
TX packets 63476 bytes 6153022 (6.1 MB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 16 memory 0xdf400000-df420000
enp3s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.16.10.120 netmask 255.255.254.0 broadcast 172.16.11.255
inet6 fe80::c600:adff:fe38:7cc9 prefixlen 64 scopeid 0x20<link>
ether c4:00:ad:38:7c:c9 txqueuelen 1000 (Ethernet)
RX packets 460878 bytes 40248747 (40.2 MB)
RX errors 0 dropped 284630 overruns 0 frame 0
TX packets 2964 bytes 336067 (336.0 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device memory 0xdf200000-df2fffff
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 329 bytes 29072 (29.0 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 329 bytes 29072 (29.0 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
现在我只能通过 ssh 连接到 172.16.11.39，但无法连接到 DHCP 分配的 ip 172.16.10.120。这是什么原因造成的，我该如何修复？