diff --git a/cmd/tailscale/depaware.txt b/cmd/tailscale/depaware.txt
index 3adfe7c62..dfc160e37 100644
--- a/cmd/tailscale/depaware.txt
+++ b/cmd/tailscale/depaware.txt
@@ -22,7 +22,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         tailscale.com/derp                                           from tailscale.com/derp/derphttp
         tailscale.com/derp/derphttp                                  from tailscale.com/net/netcheck
         tailscale.com/disco                                          from tailscale.com/derp
-        tailscale.com/hostinfo                                       from tailscale.com/net/interfaces+
+        tailscale.com/hostinfo                                       from tailscale.com/net/interfaces
         tailscale.com/ipn                                            from tailscale.com/cmd/tailscale/cli+
         tailscale.com/ipn/ipnstate                                   from tailscale.com/cmd/tailscale/cli+
         tailscale.com/metrics                                        from tailscale.com/derp
diff --git a/hostinfo/hostinfo.go b/hostinfo/hostinfo.go
index 791da939c..58c8e9de3 100644
--- a/hostinfo/hostinfo.go
+++ b/hostinfo/hostinfo.go
@@ -9,7 +9,6 @@
 package hostinfo
 
 import (
-	"flag"
 	"io"
 	"os"
 	"runtime"
@@ -29,7 +28,6 @@ const (
 	Heroku          = EnvType("hr")
 	AzureAppService = EnvType("az")
 	AWSFargate      = EnvType("fg")
-	TestCase        = EnvType("tc")
 )
 
 var envType atomic.Value // of EnvType
@@ -44,11 +42,6 @@ func GetEnvType() EnvType {
 }
 
 func getEnvType() EnvType {
-	// inTestCase needs to go first. If running tests in a container, we want
-	// the environment to be TestCase not the type of container.
-	if inTestCase() {
-		return TestCase
-	}
 	if inKnative() {
 		return KNative
 	}
@@ -91,13 +84,6 @@ func InContainer() bool {
 	return ret
 }
 
-func inTestCase() bool {
-	if flag.CommandLine.Lookup("test.v") != nil {
-		return true
-	}
-	return false
-}
-
 func inKnative() bool {
 	// https://cloud.google.com/run/docs/reference/container-contract#env-vars
 	if os.Getenv("K_REVISION") != "" && os.Getenv("K_CONFIGURATION") != "" &&
diff --git a/net/netns/netns_linux.go b/net/netns/netns_linux.go
index 42834338c..c12d000e8 100644
--- a/net/netns/netns_linux.go
+++ b/net/netns/netns_linux.go
@@ -15,7 +15,6 @@ import (
 	"syscall"
 
 	"golang.org/x/sys/unix"
-	"tailscale.com/hostinfo"
 	"tailscale.com/net/interfaces"
 )
 
@@ -75,14 +74,6 @@ func useSocketMark() bool {
 // ignoreErrors returns true if we should ignore setsocketopt errors in
 // this instance.
 func ignoreErrors() bool {
-	// If we're in a test, ignore errors. Assume the test knows
-	// what it's doing and will do its own skips or permission
-	// checks if it's setting up a world that needs netns to work.
-	// But by default, assume that tests don't need netns and it's
-	// harmless to ignore the sockopts failing.
-	if hostinfo.GetEnvType() == hostinfo.TestCase {
-		return true
-	}
 	if os.Getuid() != 0 {
 		// only root can manipulate these socket flags
 		return true
@@ -95,9 +86,6 @@ func ignoreErrors() bool {
 // It's intentionally the same signature as net.Dialer.Control
 // and net.ListenConfig.Control.
 func control(network, address string, c syscall.RawConn) error {
-	if hostinfo.GetEnvType() == hostinfo.TestCase {
-		return nil
-	}
 	if isLocalhost(address) {
 		// Don't bind to an interface for localhost connections.
 		return nil