Need help debugging a VPN interaction with Docker

Environment:

  • Pop!_OS 22.04 LTS
  • hostname: kindzadza
  • Docker version 20.10.12, build e91ed57
  • Docker Compose version v2.2.3
  • Cisco AnyConnect Secure Mobility Client Version 4.10.00093

When I try to access IPs that are only accessible via VPN from within a Docker container, the connection stalls at my home gateway. When I try the same IP from my laptop, the connection is made.

I will illustrate the differences with two addresses: one called restricted (protected by VPN) and one called free. I will paste the output of traceroute for the following combinations: restricted + host, restricted + docker, free + docker.

restricted + host

traceroute to restricted (142.34.150.155), 30 hops max, 60 byte packets
 1  kamrc005.lan.net.gov.bc.ca (142.28.96.1)  48.819 ms  48.761 ms  48.739 ms
 2  tgobc-span-esit-kdc.net.gov.bc.ca (142.24.40.91)  48.648 ms  48.625 ms  48.612 ms
 3  172.30.0.136 (172.30.0.136)  48.489 ms  48.539 ms  48.558 ms

restricted + docker

traceroute to restricted (142.34.150.155), 30 hops max, 46 byte packets
 1  kindzadza.local (172.20.0.1)  0.008 ms  0.010 ms  0.003 ms
 2  *  *  *
 3  *  *  *
 4^C

free + docker

traceroute to free (18.172.170.73), 30 hops max, 46 byte packets
 1  kindzadza.local (172.20.0.1)  0.006 ms  0.008 ms  0.005 ms
 2  _gateway (192.168.0.1)  4.220 ms  1.741 ms  2.675 ms
 3  50.64.0.1 (50.64.0.1)  17.981 ms  13.566 ms  13.814 ms
 4  rc1bb-be110-1.vc.shawcable.net (64.59.152.9)  55.068 ms  17.266 ms  17.719 ms
 5  24.244.58.233 (24.244.58.233)  15.124 ms  27.050 ms  19.969 ms
 6  24.244.63.105 (24.244.63.105)  15.007 ms  13.630 ms  18.798 ms
 7  rc1bb-be214.vc.shawcable.net (24.244.58.61)  15.051 ms  16.255 ms  15.172 ms
 8  rc1wt.wa.shawcable.net (66.163.76.66)  25.166 ms  54.153 ms  20.853 ms
 9  99.82.176.40 (99.82.176.40)  17.836 ms  20.408 ms  17.060 ms

There are so many layers here that I am not sure how to go about debugging this issue. Any help would be appreciated. Thanks!