diff --git a/mypy.ini b/mypy.ini
index a68b8b0e837..d26f652e0fa 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -238,21 +238,6 @@ warn_return_any = False
 
 # Disable warn_unreachable for some modules until we clean them up
 
-[mypy-twisted.conch.scripts.conch]
-warn_unreachable = False
-
-[mypy-twisted.conch.telnet]
-warn_unreachable = False
-
-[mypy-twisted.conch.test.test_agent]
-warn_unreachable = False
-
-[mypy-twisted.conch.test.test_connection]
-warn_unreachable = False
-
-[mypy-twisted.conch.test.test_ssh]
-warn_unreachable = False
-
 [mypy-twisted.internet.defer]
 warn_unreachable = False
 
diff --git a/src/twisted/conch/scripts/conch.py b/src/twisted/conch/scripts/conch.py
index 504eb8c452e..bc7683a6639 100644
--- a/src/twisted/conch/scripts/conch.py
+++ b/src/twisted/conch/scripts/conch.py
@@ -313,10 +313,6 @@ def serviceStarted(self):
         conn = self
         self.localForwards = []
         self.remoteForwards = {}
-        if not isinstance(self, connection.SSHConnection):
-            # make these fall through
-            del self.__class__.requestRemoteForwarding
-            del self.__class__.cancelRemoteForwarding
         onConnect()
 
     def serviceStopped(self):
diff --git a/src/twisted/conch/telnet.py b/src/twisted/conch/telnet.py
index 6a337f9fe25..a7e36e5988f 100644
--- a/src/twisted/conch/telnet.py
+++ b/src/twisted/conch/telnet.py
@@ -1015,12 +1015,12 @@ def telnet_NAWS(self, data):
     linemodeSubcommands = {LINEMODE_SLC: "SLC"}
 
     def telnet_LINEMODE(self, data):
-        linemodeSubcommand = data[0]
-        if 0:
-            # XXX TODO: This should be enabled to parse linemode subnegotiation.
-            getattr(self, "linemode_" + self.linemodeSubcommands[linemodeSubcommand])(
-                data[1:]
-            )
+        # linemodeSubcommand = data[0]
+        # # XXX TODO: This should be enabled to parse linemode subnegotiation.
+        # getattr(self, "linemode_" + self.linemodeSubcommands[linemodeSubcommand])(
+        #     data[1:]
+        # )
+        pass
 
     def linemode_SLC(self, data):
         chunks = zip(*[iter(data)] * 3)
diff --git a/src/twisted/conch/test/test_agent.py b/src/twisted/conch/test/test_agent.py
index 2a33a5e29f7..cc3a794969c 100644
--- a/src/twisted/conch/test/test_agent.py
+++ b/src/twisted/conch/test/test_agent.py
@@ -11,19 +11,20 @@
 from twisted.test import iosim
 
 try:
-    import cryptography
+    import cryptography as _cryptography
 except ImportError:
-    cryptography = None  # type: ignore[assignment]
+    cryptography = None
+else:
+    cryptography = _cryptography
 
 try:
-    import pyasn1
+    import pyasn1 as _pyasn1
 except ImportError:
     pyasn1 = None
-
-if cryptography and pyasn1:
-    from twisted.conch.ssh import keys, agent
 else:
-    keys = agent = None  # type: ignore[assignment]
+    pyasn1 = _pyasn1
+
+from twisted.conch.ssh import keys, agent
 
 from twisted.conch.test import keydata
 from twisted.conch.error import ConchError, MissingKeyStoreError
@@ -44,11 +45,6 @@ class AgentTestBase(unittest.TestCase):
     Tests for SSHAgentServer/Client.
     """
 
-    if iosim is None:
-        skip = "iosim requires SSL, but SSL is not available"
-    elif agent is None or keys is None:
-        skip = "Cannot run without cryptography or PyASN1"
-
     def setUp(self):
         # wire up our client <-> server
         self.client, self.server, self.pump = iosim.connectedServerAndClient(
@@ -120,20 +116,18 @@ def test_agentc_REMOVE_ALL_RSA_IDENTITIES(self):
         return d.addCallback(self.assertEqual, b"")
 
 
-if agent is not None:
-
-    class CorruptServer(agent.SSHAgentServer):
-        """
-        A misbehaving server that returns bogus response op codes so that we can
-        verify that our callbacks that deal with these op codes handle such
-        miscreants.
-        """
+class CorruptServer(agent.SSHAgentServer):
+    """
+    A misbehaving server that returns bogus response op codes so that we can
+    verify that our callbacks that deal with these op codes handle such
+    miscreants.
+    """
 
-        def agentc_REQUEST_IDENTITIES(self, data):
-            self.sendResponse(254, b"")
+    def agentc_REQUEST_IDENTITIES(self, data):
+        self.sendResponse(254, b"")
 
-        def agentc_SIGN_REQUEST(self, data):
-            self.sendResponse(254, b"")
+    def agentc_SIGN_REQUEST(self, data):
+        self.sendResponse(254, b"")
 
 
 class ClientWithBrokenServerTests(AgentTestBase):
diff --git a/src/twisted/conch/test/test_connection.py b/src/twisted/conch/test/test_connection.py
index fdbd552d8cd..ed7fe6a61ec 100644
--- a/src/twisted/conch/test/test_connection.py
+++ b/src/twisted/conch/test/test_connection.py
@@ -206,8 +206,6 @@ class ConnectionTests(unittest.TestCase):
 
     if not cryptography:
         skip = "Cannot run without cryptography"
-    if test_userauth.transport is None:
-        skip = "Cannot run without both cryptography and pyasn1"
 
     def setUp(self):
         self.transport = test_userauth.FakeTransport(None)
@@ -830,9 +828,6 @@ class CleanConnectionShutdownTests(unittest.TestCase):
     if not cryptography:
         skip = "Cannot run without cryptography"
 
-    if test_userauth.transport is None:
-        skip = "Cannot run without both cryptography and pyasn1"
-
     def setUp(self):
         self.transport = test_userauth.FakeTransport(None)
         self.transport.avatar = TestAvatar()
diff --git a/src/twisted/conch/test/test_ssh.py b/src/twisted/conch/test/test_ssh.py
index e174e53214d..c0c0d3d2d12 100644
--- a/src/twisted/conch/test/test_ssh.py
+++ b/src/twisted/conch/test/test_ssh.py
@@ -410,8 +410,6 @@ def receiveError(self, reasonCode, desc):
 
         def receiveUnimplemented(self, seqID):
             raise unittest.FailTest("got unimplemented: seqid %s" % (seqID,))
-            self.expectedLoseConnection = 1
-            self.loseConnection()
 
     class ConchTestServer(ConchTestBase, transport.SSHServerTransport):
         def connectionLost(self, reason):