diff --git a/toad/src/step/block.rs b/toad/src/step/block.rs
index a85f2e6..a6a0c45 100644
--- a/toad/src/step/block.rs
+++ b/toad/src/step/block.rs
@@ -86,16 +86,8 @@ impl<P, Pieces> Conversation<P, Pieces>
         Pieces: Default
 {
   /// Create a new [`Conversation`] tracking a Blocked response to a sent request (param `msg`)
-  pub fn expect_response(expires_at: Instant<P::Clock>, msg: Message<P>) -> Self {
-    Self { original: Some(msg),
-           biggest_number_seen: None,
-           pcs: Default::default(),
-           expires_at }
-  }
-
-  /// Create a new [`Conversation`] tracking a received Blocked request
-  pub fn request(expires_at: Instant<P::Clock>) -> Self {
-    Self { original: None,
+  pub fn new(expires_at: Instant<P::Clock>, original: Option<Message<P>>) -> Self {
+    Self { original,
            biggest_number_seen: None,
            pcs: Default::default(),
            expires_at }
@@ -280,21 +272,13 @@ impl<P, S, Endpoints, Conversations, Pieces> Block<P, S, Endpoints, Conversation
                   })
   }
 
-  fn expect_response(&self, snap: &Snapshot<P>, addr: SocketAddr, req: &Message<P>) {
-    let exp = snap.time + Milliseconds(snap.config.exchange_lifetime_millis());
-    self.get_or_create_endpoint(addr, |convs| {
-          convs.insert((req.token, Role::Response, Direction::Inbound),
-                       Conversation::expect_response(exp, req.clone()))
-               .unwrap();
-        });
-  }
-
-  fn insert_request(&self,
+  fn insert(&self,
                     snap: &Snapshot<P>,
+                    original: Option<&Message<P>>,
                     (addr, token, role, dir): (SocketAddr, Token, Role, Direction)) {
     let exp = snap.time + Milliseconds(snap.config.exchange_lifetime_millis());
     self.get_or_create_endpoint(addr, |convs| {
-          convs.insert((token, role, dir), Conversation::request(exp))
+          convs.insert((token, role, dir), Conversation::new(exp, original.cloned()))
                .unwrap();
         });
   }
@@ -391,7 +375,7 @@ impl<P, S, Endpoints, Conversations, Pieces> Step<P>
       },
       | Some(block) => {
         if !has_prev_pieces && block.num() == 0 && block.more() {
-          self.insert_request(snap, k);
+          self.insert(snap, None, k);
           self.map_mut(k, |conv| {
                 conv.have(snap.time, 0, req.clone().map(|r| r.into()).unwrap())
               });
@@ -467,7 +451,7 @@ impl<P, S, Endpoints, Conversations, Pieces> Step<P>
       },
       | Some(block) => {
         if !has_prev_pieces {
-          // TODO: warn
+          log!(Block::poll_resp, effects, log::Level::Warn, "Response received for token {:?} but we've never seen a request using that token. Ignoring this response despite it having {:?}", rep.data().msg().token, block);
           Some(Ok(rep))
         } else {
           self.map_mut(k, |conv| {
@@ -496,16 +480,48 @@ impl<P, S, Endpoints, Conversations, Pieces> Step<P>
     }
   }
 
+  fn before_message_sent(&self,
+                     snap: &platform::Snapshot<P>,
+                     effs: &mut P::Effects,
+                     msg: &mut Addrd<Message<P>>)
+                     -> Result<(), Self::Error> {
+    self.prune(effs, snap.time);
+    self.inner.before_message_sent(snap, effs, msg)?;
+
+    let block_size: usize = 1024;
+
+    let original_payload = msg.data().payload().0;
+
+    // TODO: block if 1024 is too big and we got REQUEST_ENTITY_TOO_LARGE
+    if msg.data().block1().is_none() && original_payload.len() > block_size {
+        let k = (msg.addr(), msg.data().token, Role::Request, Direction::Outbound);
+      self.insert(snap, Some(msg.data()), k);
+      self.map_mut(k, |conv| {
+        let len = original_payload.len() as f32;
+        let block_count = (len / block_size as f32).ceil() as u32;
+        for n in 0..block_count {
+          let mut msg_block = msg.clone();
+          msg_block.as_mut().set_block1(1024, n, n == block_count - 1).ok();
+          let mut p = P::MessagePayload::default();
+          p.append_copy(original_payload[n * 1024..((n + 1) * 1024)]);
+          msg_block.as_mut().payload = Payload(p);
+          conv.have(snap.time, n, msg_block.unwrap());
+        }
+      }).unwrap();
+    }
+    Ok(())
+  }
+
   fn on_message_sent(&self,
                      snap: &platform::Snapshot<P>,
                      effs: &mut P::Effects,
                      msg: &Addrd<Message<P>>)
                      -> Result<(), Self::Error> {
-    self.prune(effs, snap.time);
     self.inner.on_message_sent(snap, effs, msg)?;
     if msg.data().code.kind() == CodeKind::Request {
-      self.expect_response(snap, msg.addr(), msg.data());
+      self.insert(snap, Some(msg.data()), (msg.addr(), msg.data().token, Role::Response, Direction::Inbound));
     } else if msg.data().code.kind() == CodeKind::Response {
+      // TODO: block outbound responses
     }
 
     Ok(())