Two apps use Network Extensions in the same time

We have noticed a strange problem when two apps that use Network Extensions (AppProxy and Filter) run in the same time.
When this happens, TCP connection of any client app that uses a new network API like Safari or ssh breaks unexpectedly.
ssh gives "write: Broken pipe" error. (The connection is established but it breaks on the first write).

If ssh connects using IP address instead of hostname the problem does not occur!

Please note that AppProxy (NETransparentProxyProvider::handleNewFlow) just returns false (bypass the flow). The filtering extension does not block the flow as well.

Is it a known problem? If no, I can provide more info.
I have not seen this myself, but my recommendation would be to open a TSI so I can dedicate some research time to investigating this issue.


Matt Eaton
DTS Engineering, CoreOS
meaton3@apple.com
I have submitted TSI 753464789.

It turned out that the problem happens when any NETransparentProxyProvider and NEFilterDataProvider run together on the system (same app or not).

The problem persists in Big Sur 11.1 beta as well.
Two apps use Network Extensions in the same time
 
 
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