Tweaking WebRTC and Loopback adapter?

Question

linux

Good evening everyone. There is such an instruction for 'fine tuning' WebRTC, on a Windows virtual machine. You need to do the same, only under the localhost on Ubuntu. What was done? The iptables rules are written to block unnecessary udp traffic:

iptables -A OUTPUT -o lo -j ACCEPT #Разрешаем локальный трафик
iptables -A OUTPUT -p udp --dport 53 -j ACCEPT #Разрешаем трафик для DNS сервера
iptables -A OUTPUT -p udp -j DROP #Запрещаем остальной udp трафик

Further, according to the idea, you need to set up a route, and this is where problems arose. Let's say I want my external WebRTC to be 127.0.0.1. I write the following

route add -net 127.0.0.1 netmask 255.255.255.255 gateway 100.76.74.62 ppp0

But nothing has changed (restarted networking). Here is what the ifconfig command says:

enp3s0    Link encap:Ethernet  HWaddr 4c:72:b9:46:d9:53  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Локальная петля (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:2149 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2149 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:144334 (144.3 KB)  TX bytes:144334 (144.3 KB)

ppp0      Link encap:Протокол PPP (Point-to-Point Protocol)  
          inet addr:100.76.74.62  P-t-P:0.0.0.0  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
          RX packets:392596 errors:0 dropped:0 overruns:0 frame:0
          TX packets:244084 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3 
          RX bytes:510464211 (510.4 MB)  TX bytes:22995525 (22.9 MB)

wlp4s0    Link encap:Ethernet  HWaddr 00:08:ca:f9:2d:e2  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

wlp4s0 is the internal network card. ppp0 - usb modem (in this example, it acts as a device through which Internet access is provided), enp3s0 - lan cable. Question: what am I doing wrong? And do I do that at all? What do you say?
UDP : 127.0.0.1 is taken as an example. As far as I understood correctly, for the desired ip, you need to change the lo address of the adapter and change the settings for it accordingly.