diff --git a/lib/net/peer.js b/lib/net/peer.js
index ef03fc9c..5b83a4be 100644
--- a/lib/net/peer.js
+++ b/lib/net/peer.js
@@ -12,6 +12,7 @@ var EventEmitter = require('events').EventEmitter;
 var utils = require('../utils/utils');
 var spawn = require('../utils/spawn');
 var co = spawn.co;
+var wrap = spawn.wrap;
 var Parser = require('./parser');
 var Framer = require('./framer');
 var packets = require('./packets');
@@ -106,6 +107,7 @@ function Peer(pool, addr, socket) {
   this.bip150 = null;
   this.lastSend = 0;
   this.lastRecv = 0;
+  this.outgoing = 0;
 
   this.challenge = null;
   this.lastPong = -1;
@@ -744,25 +746,30 @@ Peer.prototype.destroy = function destroy() {
 /**
  * Write data to the peer's socket.
  * @param {Buffer} data
- * @returns {Boolean}
+ * @returns {Promise}
  */
 
 Peer.prototype.write = function write(data) {
+  var self = this;
+
   if (this.destroyed)
-    return false;
+    return Promise.resolve(null);
 
   this.lastSend = utils.ms();
 
-  return this.socket.write(data);
+  return new Promise(function(resolve, reject) {
+    self.socket.write(data, wrap(resolve, reject));
+  });
 };
 
 /**
  * Send a packet.
  * @param {Packet} packet
+ * @returns {Promise}
  */
 
 Peer.prototype.send = function send(packet) {
-  var tx, checksum;
+  var tx, checksum, payload;
 
   // Used cached hashes as the
   // packet checksum for speed.
@@ -776,9 +783,29 @@ Peer.prototype.send = function send(packet) {
     }
   }
 
-  this.write(this.framer.packet(packet.cmd, packet.toRaw(), checksum));
+  payload = this.framer.packet(packet.cmd, packet.toRaw(), checksum);
+
+  return this.write(payload);
 };
 
+/**
+ * Send a packet. Throttle reads and wait for flush.
+ * @param {Packet} packet
+ * @returns {Promise}
+ */
+
+Peer.prototype.flush = co(function* flush(packet) {
+  assert(this.outgoing >= 0);
+
+  if (this.outgoing++ === 0)
+    this.socket.pause();
+
+  yield this.send(packet);
+
+  if (--this.outgoing === 0)
+    this.socket.resume();
+});
+
 /**
  * Emit an error and destroy the peer.
  * @private
@@ -1528,7 +1555,7 @@ Peer.prototype._handleGetData = co(function* _handleGetData(packet) {
  * @param {GetDataPacket}
  */
 
-Peer.prototype._handleGetData = co(function* _handleGetData(packet) {
+Peer.prototype.__handleGetData = co(function* _handleGetData(packet) {
   var notFound = [];
   var items = packet.items;
   var i, j, item, entry, tx, block;
@@ -1560,7 +1587,7 @@ Peer.prototype._handleGetData = co(function* _handleGetData(packet) {
         continue;
       }
 
-      this.send(new packets.TXPacket(tx, item.hasWitness()));
+      yield this.flush(new packets.TXPacket(tx, item.hasWitness()));
 
       continue;
     }
@@ -1570,7 +1597,7 @@ Peer.prototype._handleGetData = co(function* _handleGetData(packet) {
     switch (item.type) {
       case constants.inv.BLOCK:
       case constants.inv.WITNESS_BLOCK:
-        this.send(new packets.BlockPacket(block, item.hasWitness()));
+        yield this.flush(new packets.BlockPacket(block, item.hasWitness()));
         break;
       case constants.inv.FILTERED_BLOCK:
       case constants.inv.WITNESS_FILTERED_BLOCK:
@@ -1581,18 +1608,18 @@ Peer.prototype._handleGetData = co(function* _handleGetData(packet) {
 
         block = block.toMerkle(this.spvFilter);
 
-        this.send(new packets.MerkleBlockPacket(block));
+        yield this.flush(new packets.MerkleBlockPacket(block));
 
         for (j = 0; j < block.txs.length; j++) {
           tx = block.txs[j];
-          this.send(new packets.TXPacket(tx, item.hasWitness()));
+          yield this.flush(new packets.TXPacket(tx, item.hasWitness()));
         }
 
         break;
       case constants.inv.CMPCT_BLOCK:
         // Fallback to full block.
         if (block.height < this.chain.tip.height - 10) {
-          this.send(new packets.BlockPacket(block, false));
+          yield this.flush(new packets.BlockPacket(block, false));
           break;
         }
 
@@ -1607,7 +1634,7 @@ Peer.prototype._handleGetData = co(function* _handleGetData(packet) {
           break;
         }
 
-        this.send(new packets.CmpctBlockPacket(block, false));
+        yield this.flush(new packets.CmpctBlockPacket(block, false));
         break;
       default:
         this.logger.warning(
@@ -2157,7 +2184,8 @@ Peer.prototype._handleGetBlockTxn = co(function* _handleGetBlockTxn(packet) {
 
   res = bcoin.bip152.TXResponse.fromBlock(block, req);
 
-  this.send(new packets.BlockTxnPacket(res, false));
+  yield this.flush(new packets.BlockTxnPacket(res, false));
+
   this.fire('blocktxn', req);
 });
 
diff --git a/lib/net/proxysocket.js b/lib/net/proxysocket.js
index 2c988591..14543dff 100644
--- a/lib/net/proxysocket.js
+++ b/lib/net/proxysocket.js
@@ -129,9 +129,13 @@ ProxySocket.prototype.connect = function connect(port, host) {
   this.sendBuffer.length = 0;
 };
 
-ProxySocket.prototype.write = function write(data) {
+ProxySocket.prototype.write = function write(data, callback) {
   if (!this.info) {
     this.sendBuffer.push(data);
+
+    if (callback)
+      callback();
+
     return true;
   }
 
@@ -139,6 +143,9 @@ ProxySocket.prototype.write = function write(data) {
 
   this.socket.emit('tcp data', data.toString('hex'));
 
+  if (callback)
+    callback();
+
   return true;
 };