diff --git a/README.md b/README.md
index 8aac47fd..91baebb2 100644
--- a/README.md
+++ b/README.md
@@ -141,6 +141,11 @@ Options:
 
 > Used in `SITE CHMOD`
 
+`getUniqueName()`
+> Return a unique file name to write to
+
+> Used in `STOU`
+
 <!--[RM_CONTRIBUTING]-->
 ## Contributing
 
diff --git a/src/commands/index.js b/src/commands/index.js
index 5d5c10b7..a5a0edd2 100644
--- a/src/commands/index.js
+++ b/src/commands/index.js
@@ -5,7 +5,6 @@ const REGISTRY = require('./registry');
 
 class FtpCommands {
   constructor(connection) {
-    console.log(REGISTRY)
     this.connection = connection;
     this.previousCommand = {};
     this.blacklist = _.get(this.connection, 'server.options.blacklist', []).map(cmd => _.upperCase(cmd));
@@ -31,7 +30,7 @@ class FtpCommands {
     const commandRegister = REGISTRY[command.directive];
     const commandFlags = _.get(commandRegister, 'flags', {});
     if (!commandFlags.no_auth && !this.connection.authenticated) {
-      return this.connection.reply(530);
+      return this.connection.reply(530, 'Command requires authentication');
     }
 
     if (!commandRegister.handler) {
diff --git a/src/commands/registration/abor.js b/src/commands/registration/abor.js
new file mode 100644
index 00000000..2ec2664b
--- /dev/null
+++ b/src/commands/registration/abor.js
@@ -0,0 +1,14 @@
+module.exports = {
+  directive: 'ABOR',
+  handler: function () {
+    return this.connector.waitForConnection()
+    .then(socket => {
+      return this.reply(426, {socket})
+      .then(() => this.connector.end());
+    })
+    .catch(() => {})
+    .then(() => this.reply(226));
+  },
+  syntax: '{{cmd}}',
+  description: 'Abort an active file transfer'
+};
diff --git a/src/commands/registration/mode.js b/src/commands/registration/mode.js
index 31ba113c..994a6ad0 100644
--- a/src/commands/registration/mode.js
+++ b/src/commands/registration/mode.js
@@ -1,7 +1,7 @@
 module.exports = {
   directive: 'MODE',
   handler: function ({command} = {}) {
-    return this.reply(command._[1] === 'S' ? 200 : 504);
+    return this.reply(/^S$/i.test(command._[1]) ? 200 : 504);
   },
   syntax: '{{cmd}} [mode]',
   description: 'Sets the transfer mode (Stream, Block, or Compressed)',
diff --git a/src/commands/registration/stor.js b/src/commands/registration/stor.js
index 8f6c36b7..cc8d910b 100644
--- a/src/commands/registration/stor.js
+++ b/src/commands/registration/stor.js
@@ -7,6 +7,7 @@ module.exports = {
     if (!this.fs.write) return this.reply(402, 'Not supported by file system');
 
     const append = command.directive === 'APPE';
+    const fileName = command._[1];
 
     let dataSocket;
     return this.connector.waitForConnection()
@@ -14,12 +15,12 @@ module.exports = {
       this.commandSocket.pause();
       dataSocket = socket;
     })
-    .then(() => when(this.fs.write(command._[1], {append})))
+    .then(() => when(this.fs.write(fileName, {append})))
     .then(stream => {
       return when.promise((resolve, reject) => {
         stream.on('error', err => dataSocket.emit('error', err));
 
-        dataSocket.on('end', () => stream.end(() => resolve(this.reply(226))));
+        dataSocket.on('end', () => stream.end(() => resolve(this.reply(226, fileName))));
         dataSocket.on('error', err => reject(err));
         dataSocket.on('data', data => stream.write(data, this.encoding));
         this.reply(150).then(() => dataSocket.resume());
diff --git a/src/commands/registration/stou.js b/src/commands/registration/stou.js
new file mode 100644
index 00000000..9582315f
--- /dev/null
+++ b/src/commands/registration/stou.js
@@ -0,0 +1,20 @@
+const stor = require('./stor').handler;
+
+module.exports = {
+  directive: 'STOU',
+  handler: function (args) {
+    if (!this.fs) return this.reply(550, 'File system not instantiated');
+    if (!this.fs.get || !this.fs.getUniqueName) return this.reply(402, 'Not supported by file system');
+
+    const fileName = args.command._[1];
+    return this.fs.get(fileName)
+    .catch(() => fileName)                // does not exist, name is unique
+    .then(() => this.fs.getUniqueName())  // exists, must create new unique name
+    .then(name => {
+      args.command._[1] = name;
+      return stor.call(this, args);
+    });
+  },
+  syntax: '{{cmd}}',
+  description: 'Store file uniquely'
+};
diff --git a/src/commands/registration/stru.js b/src/commands/registration/stru.js
index d025e129..68470c15 100644
--- a/src/commands/registration/stru.js
+++ b/src/commands/registration/stru.js
@@ -1,7 +1,7 @@
 module.exports = {
   directive: 'STRU',
   handler: function ({command} = {}) {
-    return this.reply(command._[1] === 'F' ? 200 : 504);
+    return this.reply(/^F$/i.test(command._[1]) ? 200 : 504);
   },
   syntax: '{{cmd}} [structure]',
   description: 'Set file transfer structure',
diff --git a/src/commands/registration/user.js b/src/commands/registration/user.js
index 2e7fc442..b8a26081 100644
--- a/src/commands/registration/user.js
+++ b/src/commands/registration/user.js
@@ -1,7 +1,6 @@
 module.exports = {
   directive: 'USER',
   handler: function ({log, command} = {}) {
-    console.log('HANDLE USER')
     if (this.username) return this.reply(530, 'Username already set');
     this.username = command._[1];
     if (this.server.options.anonymous === true) {
diff --git a/src/commands/registry.js b/src/commands/registry.js
index 25dd038e..12ab5726 100644
--- a/src/commands/registry.js
+++ b/src/commands/registry.js
@@ -1,4 +1,5 @@
 const commands = [
+  require('./registration/abor'),
   require('./registration/allo'),
   require('./registration/appe'),
   require('./registration/auth'),
@@ -26,6 +27,7 @@ const commands = [
   require('./registration/size'),
   require('./registration/stat'),
   require('./registration/stor'),
+  require('./registration/stou'),
   require('./registration/stru'),
   require('./registration/syst'),
   require('./registration/type'),
diff --git a/src/connection.js b/src/connection.js
index fec36908..3fa7fdc1 100644
--- a/src/connection.js
+++ b/src/connection.js
@@ -2,7 +2,7 @@ const _ = require('lodash');
 const uuid = require('uuid');
 const when = require('when');
 const sequence = require('when/sequence');
-const parseSentence = require('minimist-string');
+const parseCommandString = require('minimist-string');
 const net = require('net');
 
 const BaseConnector = require('./connector/base');
@@ -16,28 +16,26 @@ class FtpConnection {
     this.server = server;
     this.commandSocket = options.socket;
     this.id = uuid.v4();
-    this.log = options.log.child({ftp_session_id: this.commandSocket.ftp_session_id});
+    this.log = options.log.child({id: this.id});
     this.commands = new Commands(this);
     this.encoding = 'utf-8';
 
     this.connector = new BaseConnector(this);
 
     this.commandSocket.on('error', err => {
-      console.log('error', err)
+      this.server.server.emit('error', {connection: this, error: err});
     });
     this.commandSocket.on('data', data => {
       const messages = _.compact(data.toString('utf-8').split('\r\n'));
       const handleMessage = (message) => {
-        const command = parseSentence(message);
+        const command = parseCommandString(message);
         command.directive = _.upperCase(command._[0]);
         return this.commands.handle(command);
       };
 
       return sequence(messages.map(message => handleMessage.bind(this, message)));
     });
-    this.commandSocket.on('timeout', () => {
-      console.log('timeout')
-    });
+    this.commandSocket.on('timeout', () => {});
     this.commandSocket.on('close', () => {
       if (this.connector) this.connector.end();
       if (this.commandSocket && !this.commandSocket.destroyed) this.commandSocket.destroy();
diff --git a/src/connector/active.js b/src/connector/active.js
index 68f02c98..b4dde230 100644
--- a/src/connector/active.js
+++ b/src/connector/active.js
@@ -8,12 +8,12 @@ class Active extends Connector {
     this.type = 'active';
   }
 
-  waitForConnection() {
+  waitForConnection({timeout = 5000, delay = 250} = {}) {
     return when.iterate(
       () => {},
       () => this.dataSocket && this.dataSocket.connected,
-      () => when().delay(250)
-    ).timeout(5000)
+      () => when().delay(delay)
+    ).timeout(timeout)
     .then(() => this.dataSocket);
   }
 
diff --git a/src/connector/base.js b/src/connector/base.js
index 922ae54c..4e7a61ad 100644
--- a/src/connector/base.js
+++ b/src/connector/base.js
@@ -21,8 +21,7 @@ class Connector {
     if (this.dataServer) this.dataServer.close();
     this.dataSocket = null;
     this.dataServer = null;
-
-    this.connection.connector = new Connector(this.connection);
+    this.type = false;
   }
 }
 module.exports = Connector;
diff --git a/src/connector/passive.js b/src/connector/passive.js
index 535c51a0..8ed2662a 100644
--- a/src/connector/passive.js
+++ b/src/connector/passive.js
@@ -10,15 +10,15 @@ class Passive extends Connector {
     this.type = 'passive';
   }
 
-  waitForConnection() {
+  waitForConnection({timeout = 5000, delay = 250} = {}) {
     if (!this.dataServer) {
       return when.reject(new errors.ConnectorError('Passive server not setup'));
     }
     return when.iterate(
       () => {},
-      () => this.dataServer && this.dataServer.listening && this.dataSocket,
-      () => when().delay(250)
-    ).timeout(5000)
+      () => this.dataServer && this.dataServer.listening && this.dataSocket && this.dataSocket.connected,
+      () => when().delay(delay)
+    ).timeout(timeout)
     .then(() => this.dataSocket);
   }
 
@@ -44,18 +44,18 @@ class Passive extends Connector {
           return this.connection.reply(550, 'Remote addresses do not match')
           .finally(() => this.connection.close());
         }
-        this.log.info({port}, 'Passive connection fulfilled.');
+        this.log.debug({port}, 'Passive connection fulfilled.');
 
         this.dataSocket = socket;
+        this.dataSocket.connected = true;
         this.dataSocket.setEncoding(this.connection.encoding);
-        this.dataSocket.on('data', data => {
-
-        });
         this.dataSocket.on('close', () => {
+          this.log.debug('Passive connection closed');
           this.end();
         });
       });
       this.dataServer.on('close', () => {
+        this.log.debug('Passive server closed');
         this.dataServer = null;
       });
 
diff --git a/src/fs.js b/src/fs.js
index 94abab2a..c0a6a881 100644
--- a/src/fs.js
+++ b/src/fs.js
@@ -1,5 +1,6 @@
 const _ = require('lodash');
 const nodePath = require('path');
+const uuid = require('uuid');
 const when = require('when');
 const whenNode = require('when/node');
 const syncFs = require('fs');
@@ -97,5 +98,9 @@ class FileSystem {
     path = nodePath.resolve(this.cwd, path);
     return fs.chmod(path, mode);
   }
+
+  getUniqueName() {
+    return uuid.v4().replace(/\W/g, '');
+  }
 }
 module.exports = FileSystem;
diff --git a/test/start.js b/test/start.js
index 3071ef3c..be638a67 100644
--- a/test/start.js
+++ b/test/start.js
@@ -3,7 +3,8 @@ const bunyan = require('bunyan');
 
 const FtpServer = require('../src');
 
-const log = bunyan.createLogger({name: 'test', level: 10});
+const log = bunyan.createLogger({name: 'test'});
+log.level(process.env.LOG_LEVEL || 'trace');
 const server = new FtpServer(process.env.FTP_URL, {
   log,
   pasv_range: process.env.PASV_RANGE