Alwyn's Blog - networkingSometimes hyper-specific technical musingsZola2093-02-16T00:00:00+00:00https://blog.alwyn.io/tags/networking/atom.xmlWebRTC with Linux and VPN woes2093-02-16T00:00:00+00:002093-02-16T00:00:00+00:00
alveel
https://blog.alwyn.io/blog/webrtc/<h1 id="context">Context</h1>
<p>I had this weird issue with Teams where, if I was connected to the work VPN and joined a call, my entire network stack would
stop working. Whenever joining a call, I had to disable the VPN, join it, then re-enable the VPN and it would work fine.</p>
<p>If I had the problem, the only fix was to disconnect any and all network connections (not just the VPN!) and then re-enable.</p>
<p>After a bit I found out it only happens at the office. A bit later I figured out it only happens when connected over WiFi.
Wired this problem did not occur.</p>
<p>Troubleshooting was difficult at first, as networking isn't my strongest suite.</p>
<p>I had my VPN configured to only tunnel traffic that was actually directed at work networks; other traffic would go outside of it.</p>
<h1 id="fixes">Fixes</h1>
<h1 id="for-all-applications">For all applications:</h1>
<pre class="giallo" style="color: #CDD6F4; background-color: #1E1E2E;"><code data-lang="plain"><span class="giallo-l"><span>sudo firewall-cmd --permanent --direct --add-rule ipv4 filter OUTPUT 0 -s 10.8.0.0/16 ! -o tun0 -p udp -j DROP</span></span></code></pre><h1 id="for-teams-only-edit-add-config-teams-for-linux-config-json">For Teams only, edit/add <code>~/.config/teams-for-linux/config.json</code></h1>
<pre class="giallo" style="color: #CDD6F4; background-color: #1E1E2E;"><code data-lang="json"><span class="giallo-l"><span style="color: #9399B2;">{</span></span>
<span class="giallo-l"><span style="color: #9399B2;"> "</span><span style="color: #89B4FA;">network</span><span style="color: #9399B2;">": {</span></span>
<span class="giallo-l"><span style="color: #9399B2;"> "</span><span style="color: #89B4FA;">WebRtcIPHandlingPolicy</span><span style="color: #9399B2;">":</span><span style="color: #A6E3A1;"> "disable_non_proxied_udp"</span></span>
<span class="giallo-l"><span style="color: #9399B2;"> }</span></span>
<span class="giallo-l"><span style="color: #9399B2;">}</span></span></code></pre>