How to make sure that the interface does not disappear?

Question

linux

Ubuntu 16.04. Installed pptpd for PPTP connections.
When a client connects, an interface like ppp0 (ppp1, 2...) is raised, and when the client is disconnected or interrupted, the pppX interface disappears. Is it possible to "pin" these interfaces?
With client connected:
[email protected]:~# ifconfig
ens3 Link encap:Ethernet HWaddr
inet addr: Bcast: Mask:
inet6 addr: Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:11055414 errors:0 dropped:0 overruns:0 frame:0
TX packets:8998077 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:8354412375 (8.3 GB) TX bytes:10023295859 (10.0 GB)
lo Link encap:Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:2311322 errors:0 dropped:0 overruns:0 frame:0
TX packets:2311322 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:365906009 (365.9 MB) TX bytes:365906009 (365.9 MB)
ppp0 Link encap:PPP protocol (Point-to-Point Protocol)
inet addr:172.16.1.1 PtP:172.16.1.3 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1396 Metric:1
RX packets:113 errors:0 dropped:0 overruns:0 frame: 0
TX packets:84 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:19438 (19.4 KB) TX bytes:29949 (29.9 KB)
Client disabled:
[email protected]:~# ifconfig
ens3 Link encap:Ethernet HWaddr
inet addr: Bcast: Mask:
inet6 addr: Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:11055414 errors:0 dropped:0 overruns:0 frame:0
TX packets:8998077 errors: 0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:8354412375 (8.3 GB) TX bytes:10023295859 (10.0 GB)
lo Link encap:Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:2311322 errors:0 dropped:0 overruns:0 frame:0
TX packets: 2311322 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:365906009 (365.9 MB) TX bytes:365906009 (365.9 MB)

Answer 1

it is impossible
to raise it with a script, if it has fallen, from the client side