diff --git a/lib/logstash/inputs/relp.rb b/lib/logstash/inputs/relp.rb
new file mode 100644
index 000000000..6f9a444aa
--- /dev/null
+++ b/lib/logstash/inputs/relp.rb
@@ -0,0 +1,77 @@
+require "logstash/inputs/base"
+require "logstash/namespace"
+require "logstash/util/relp"
+
+
+# Read RELP events over a TCP socket.
+#
+#Application level acknowledgements allow assurance of no message loss.
+#
+#This only functions as far as messages being put into the queue for filters- 
+# anything lost after that point will not be retransmitted
+class LogStash::Inputs::Relp < LogStash::Inputs::Base
+
+  config_name "relp"
+  plugin_status "experimental"
+
+  # The address to listen on.
+  config :host, :validate => :string, :default => "0.0.0.0"
+
+  # The port to listen on.
+  config :port, :validate => :number, :required => true
+
+  def initialize(*args)
+    super(*args)
+  end # def initialize
+
+  public
+  def register
+    @logger.info("Starting relp input listener", :address => "#{@host}:#{@port}")
+    @relp_server = RelpServer.new(@host, @port,['syslog'])
+  end # def register
+
+  private
+  def relp_stream(relpsocket,output_queue,event_source)
+    loop do
+      frame = relpsocket.syslog_read
+      event = self.to_event(frame['message'],event_source)
+      output_queue << event
+      #To get this far, the message must have made it into the queue for 
+      #filtering. I don't think it's possible to wait for output before ack
+      #without fundamentally breaking the plugin architecture
+      relpsocket.ack(frame['txnr'])
+    end
+  end
+
+  public
+  def run(output_queue)
+    loop do
+      begin
+        # Start a new thread for each connection.
+        Thread.start(@relp_server.accept) do |rs|
+            @logger.debug("Relp Connection to #{rs.peer} created")
+          begin
+            relp_stream(rs,output_queue,"relp://#{@host}:#{@port}/#{rs.peer}")
+          rescue Relp::ConnectionClosed => e
+            @logger.debug("Relp Connection to #{rs.peer} Closed")
+          rescue Relp::RelpError => e
+            @logger.warn('Relp error: '+e.class.to_s+' '+e.message)
+            #TODO: Still not happy with this, are they all warn level?
+            #Will this catch everything I want it to?
+            #Relp spec says to close connection on error, ensure this is the case
+          end
+        end # Thread.start
+      rescue Relp::InvalidCommand,Relp::InappropriateCommand => e
+        @logger.warn('Relp client trying to open connection with something other than open:'+e.message)
+      rescue Relp::InsufficientCommands
+        @logger.warn('Relp client incapable of syslog')
+      end
+    end # loop
+  end # def run
+
+  def teardown
+    @relp_server.shutdown
+  end
+end # class LogStash::Inputs::Relp
+
+#TODO: structured error logging
diff --git a/lib/logstash/util/relp.rb b/lib/logstash/util/relp.rb
new file mode 100644
index 000000000..0aed09a9c
--- /dev/null
+++ b/lib/logstash/util/relp.rb
@@ -0,0 +1,321 @@
+require "socket"
+
+class Relp#This isn't much use on its own, but gives RelpServer and RelpClient things
+
+  RelpVersion = '0'#TODO: spec says this is experimental, but rsyslog still seems to exclusively use it
+  RelpSoftware = 'logstash,1.1.1,http://logstash.net'
+
+  class RelpError < StandardError; end
+  class InvalidCommand < RelpError; end
+  class InappropriateCommand < RelpError; end
+  class ConnectionClosed < RelpError; end
+  class InsufficientCommands < RelpError; end
+
+  def valid_command?(command)
+    valid_commands = Array.new
+    
+    #Allow anything in the basic protocol for both directions
+    valid_commands << 'open'
+    valid_commands << 'close'
+
+    #These are things that are part of the basic protocol, but only valid in one direction (rsp, close etc.) TODO: would they be invalid or just innapropriate?
+    valid_commands += @basic_relp_commands
+
+    #These are extra commands that we require, otherwise refuse the connection TODO: some of these are only valid on one direction
+    valid_commands += @required_relp_commands
+
+    #TODO: optional_relp_commands
+
+    #TODO: vague mentions of abort and starttls commands in spec need looking into
+    return valid_commands.include?(command)
+  end
+
+  def frame_write(frame)
+    unless self.server? #I think we have to trust a server to be using the correct txnr
+      #Only allow txnr to be 0 or be determined automatically
+      frame['txnr'] = self.nexttxnr unless frame['txnr']==0
+    end
+    frame['txnr'] = frame['txnr'].to_s
+    frame['message'] = '' if frame['message'].nil?
+    frame['datalen'] = frame['message'].length.to_s
+    wiredata=[
+      frame['txnr'],
+      frame['command'],
+      frame['datalen'],
+      frame['message']
+    ].join(' ').strip
+    begin
+      @socket.write(wiredata)
+      #Ending each frame with a newline is required in the specifications
+      #Doing it a separately is useful (but a bit of a bodge) because
+      #for some reason it seems to take 2 writes after the server closes the
+      #connection before we get an exception
+      @socket.write("\n")
+    rescue Errno::EPIPE,IOError,Errno::ECONNRESET#TODO: is this sufficient to catch all broken connections?
+      raise ConnectionClosed
+    end
+    frame['txnr'].to_i
+  end
+
+  def frame_read
+    begin
+      frame = Hash.new
+      frame['txnr'] = @socket.readline(' ').strip.to_i
+      frame['command'] = @socket.readline(' ').strip
+
+      #Things get a little tricky here because if the length is 0 it is not followed by a space.
+      leading_digit=@socket.read(1)
+      if leading_digit=='0' then
+        frame['datalen'] = 0
+        frame['message'] = ''
+      else
+        frame['datalen'] = (leading_digit + @socket.readline(' ')).strip.to_i
+        frame['message'] = @socket.read(frame['datalen'])
+      end
+    rescue EOFError,Errno::ECONNRESET,IOError
+      raise ConnectionClosed
+    end
+    if ! self.valid_command?(frame['command'])#TODO: is this enough to catch framing errors? 
+      if self.server?
+        self.serverclose
+      else
+        self.close
+      end
+      raise InvalidCommand,frame['command']
+    end
+    return frame
+  end
+
+  def server?
+    @server
+  end
+
+end
+
+class RelpServer < Relp
+  
+  def peer
+    if @peer.nil?
+      @peer = @socket.peeraddr[3]#TODO: is this the best thing to report? I don't think so...
+    end
+    @peer
+  end
+
+  def initialize(host,port,required_commands=[])
+
+    @server=true
+
+    #These are things that are part of the basic protocol, but only valid in one direction (rsp, close etc.)
+    @basic_relp_commands = ['close']#TODO: check for others
+
+    #These are extra commands that we require, otherwise refuse the connection
+    @required_relp_commands = required_commands
+
+    @server=TCPServer.new(host,port)#TODO: rescue if port is already in use (Errno::EADDRINUSE)
+  end
+  
+  def accept
+    @socket=@server.accept
+    frame=self.frame_read
+    if frame['command'] == 'open'
+      offer=Hash[*frame['message'].scan(/^(.*)=(.*)$/).flatten]
+      if offer['relp_version'].nil?
+        #if no version specified, relp spec says we must close connection
+        self.serverclose
+        raise RelpError, 'No relp_version specified'
+      #subtracting one array from the other checks to see if all elements in @required_relp_commands are present in the offer
+      elsif ! (@required_relp_commands - offer['commands'].split(',')).empty?
+        #Tell them why we're closing the connection:
+        response_frame = Hash.new
+        response_frame['txnr'] = frame['txnr']
+        response_frame['command'] = 'rsp'
+        response_frame['message'] = '500 Required command(s) '
+            + (@required_relp_commands - offer['commands'].split(',')).join(',')
+            + ' not offered'
+        self.frame_write(response_frame)
+
+        self.serverclose
+        raise InsufficientCommands, offer['commands']
+            + ' offered, require ' + @required_relp_commands.join(',')
+      else
+        #attempt to set up connection
+        response_frame = Hash.new
+        response_frame['txnr'] = frame['txnr']
+        response_frame['command'] = 'rsp'
+
+        response_frame['message'] = '200 OK '
+        response_frame['message'] += 'relp_version=' + RelpVersion + "\n"
+        response_frame['message'] += 'relp_software=' + RelpSoftware + "\n"
+        response_frame['message'] += 'commands=' + @required_relp_commands.join(',')#TODO: optional ones
+        self.frame_write(response_frame)
+        return self
+      end
+    else
+      self.serverclose
+      raise InappropriateCommand, frame['command'] + ' expecting open'
+    end
+  end
+
+  #This does not ack the frame, just reads it
+  def syslog_read
+    frame = self.frame_read
+    if frame['command'] == 'syslog'
+      return frame
+    elsif frame['command'] == 'close'
+      #the client is closing the connection, acknowledge the close and act on it
+      response_frame = Hash.new
+      response_frame['txnr'] = frame['txnr']
+      response_frame['command'] = 'rsp'
+      self.frame_write(response_frame)
+      self.serverclose
+      raise ConnectionClosed
+    else
+      #the client is trying to do something unexpected
+      self.serverclose
+      raise InappropriateCommand, frame['command'] + ' expecting syslog'
+    end
+  end
+
+  def serverclose
+    frame = Hash.new
+    frame['txnr'] = 0
+    frame['command'] = 'serverclose'
+    begin
+      self.frame_write(frame)
+      @socket.close
+    rescue ConnectionClosed
+    end
+  end
+
+  def shutdown
+    @server.shutdown
+    @server.close
+  rescue Exception#@server might already be down
+  end
+
+  def ack(txnr)
+    frame = Hash.new
+    frame['txnr'] = txnr
+    frame['command'] = 'rsp'
+    frame['message'] = '200 OK'
+    self.frame_write(frame)
+  end
+
+end
+
+#This is only used by the tests; any problems here are not as important as elsewhere
+class RelpClient < Relp
+
+  def initialize(host,port,required_commands = [],buffer_size = 128,
+                 retransmission_timeout=10)
+
+    @server = false
+    @buffer = Hash.new
+
+    @buffer_size = buffer_size
+    @retransmission_timeout = retransmission_timeout
+
+    #These are things that are part of the basic protocol, but only valid in one direction (rsp, close etc.)
+    @basic_relp_commands = ['serverclose','rsp']#TODO: check for others
+
+    #These are extra commands that we require, otherwise refuse the connection
+    @required_relp_commands = required_commands
+
+    @socket=TCPSocket.new(host,port)
+
+    #This'll start the automatic frame numbering 
+    @lasttxnr = 0
+
+    offer=Hash.new
+    offer['command'] = 'open'
+    offer['message'] = 'relp_version=' + RelpVersion + "\n"
+    offer['message'] += 'relp_software=' + RelpSoftware + "\n"
+    offer['message'] += 'commands=' + @required_relp_commands.join(',')#TODO: add optional ones
+    self.frame_write(offer)
+    response_frame = self.frame_read
+
+    unless response_frame['message'][0,3] == '200'
+      raise RelpError,response_frame['message']
+    end
+
+    response=Hash[*response_frame['message'][7..-1].scan(/^(.*)=(.*)$/).flatten]
+    if response['relp_version'].nil?
+      #if no version specified, relp spec says we must close connection
+      self.close
+      raise RelpError, 'No relp_version specified; offer: '
+          + response_frame['message'][6..-1].scan(/^(.*)=(.*)$/).flatten
+
+    #subtracting one array from the other checks to see if all elements in @required_relp_commands are present in the offer
+    elsif ! (@required_relp_commands - response['commands'].split(',')).empty?
+      #if it can't receive syslog it's useless to us; close the connection 
+      self.close
+      raise InsufficientCommands, response['commands'] + ' offered, require '
+          + @required_relp_commands.join(',')
+    end
+    #If we've got this far with no problems, we're good to go
+
+    #This thread deals with responses that come back
+    reader = Thread.start do |parent|
+      loop do
+        f = self.frame_read
+        if f['command'] == 'rsp' && f['message'] == '200 OK'
+          @buffer.delete(f['txnr'])
+        elsif f['command'] == 'rsp' && f['message'][0,1] == '5'
+          #TODO: What if we get an error for something we're already retransmitted due to timeout?
+          new_txnr = self.frame_write(@buffer[f['txnr']])
+          @buffer[new_txnr] = @buffer[f['txnr']]
+          @buffer.delete(f['txnr'])
+        elsif f['command'] == 'serverclose' || f['txnr'] == @close_txnr
+          parent.raise ConnectionClosed#TODO: raising errors like this makes no sense
+        else
+          #Don't know what's going on if we get here, but it can't be good
+          parent.raise RelpError#TODO: raising errors like this makes no sense
+        end
+      end
+    end
+
+    #While this one deals with frames for which we get no reply
+    Thread.start do
+      old_buffer = Hash.new
+      loop do
+        #This returns old txnrs that are still present
+        (@buffer.keys & old_buffer.keys).each do |txnr|
+          new_txnr = self.frame_write(@buffer[txnr])
+          @buffer[new_txnr] = @buffer[txnr]
+          @buffer.delete(txnr)
+        end
+        old_buffer = @buffer
+        sleep @retransmission_timeout
+      end
+    end
+  end
+
+  #TODO: have a way to get back unacked messages on close
+  def close
+    frame = Hash.new
+    frame['command'] = 'close'
+    @close_txnr=self.frame_write(frame)
+    #TODO: ought to properly wait for a reply etc. The serverclose will make it work though
+    sleep @retransmission_timeout
+    @socket.close#TODO: shutdown?
+    return @buffer
+  end
+
+  def syslog_write(logline)
+
+    #If the buffer is already full, wait until a gap opens up
+    sleep 0.1 until @buffer.length<@buffer_size
+
+    frame = Hash.new
+    frame['command'] = 'syslog'
+    frame['message'] = logline
+
+    txnr = self.frame_write(frame)
+    @buffer[txnr] = frame
+  end
+
+  def nexttxnr
+    @lasttxnr += 1
+  end
+
+end
diff --git a/test/logstash/inputs/test_relp.rb b/test/logstash/inputs/test_relp.rb
new file mode 100644
index 000000000..ed73f93fd
--- /dev/null
+++ b/test/logstash/inputs/test_relp.rb
@@ -0,0 +1,134 @@
+require "rubygems"
+require File.join(File.dirname(__FILE__), "..", "minitest")
+
+require "logstash/loadlibs"
+require "logstash/testcase"
+require "logstash/agent"
+require "logstash/logging"
+require "logstash/inputs/relp"
+require "logstash/util/relp"
+
+require "mocha"
+
+#TODO: I just copy/pasted all those^ which ones do I actually need?
+
+describe LogStash::Inputs::Relp do
+
+  before do
+    #TODO: port 15515 is what I tend to use; pick a default?
+    @input = LogStash::Inputs::Relp.new("type" => ["relp"],
+        "host" => ["127.0.0.1"], "port" => [15515])
+    @input.register
+  end # before
+
+  after do
+    @input.teardown
+  end # after
+
+  test "Basic handshaking/message transmission" do
+    queue = Queue.new
+    thread = Thread.new { @input.run(queue) }
+
+    # Let the input start listening. This is a crappy solution, but until
+    # plugins can notify "I am ready!" testing will be a bit awkward.
+    # TODO: could we not pull this from the logger?
+    sleep(2)
+
+    begin
+      rc=RelpClient.new('127.0.0.1',15515,['syslog'])
+      rc.syslog_write('This is the first relp test message')
+      rc.syslog_write('This is the second relp test message')
+      rc.syslog_write('This is the third relp test message')
+      rc.syslog_write('This is the fourth relp test message')
+      rc.syslog_write('This is the fifth relp test message')
+      count=5
+
+      rc.close
+
+      events=[]
+
+      start = Time.new
+  
+      # Allow maximum of 2 seconds for events to show up
+      while (Time.new - start) < 2 && events.size != count
+        begin
+          event = queue.pop(true) # don't block
+          events << event if event
+        rescue ThreadError => e
+          # Fail on anything other than "queue empty"
+          raise e if e.to_s != "queue empty"
+          sleep(0.05)
+        end
+      end
+
+      assert_equal(count, events.size, "Wanted #{count}, but got #{events.size} events")
+      assert_equal("This is the first relp test message", events.first.message)
+      assert_equal("This is the fifth relp test message", events.last.message)
+
+    rescue Relp::RelpError => re
+      flunk re.class.to_s + ': ' + re.to_s#TODO: is there not a proper way to do this?
+    end
+  end
+
+  test "RelpServer rejects invalid commands" do
+    #Need it to close the connection, but not bring down the whole server
+    queue = Queue.new
+    thread = Thread.new { @input.run(queue) }
+
+    logger=Queue.new
+    (@input.instance_eval { @logger }).subscribe(logger)
+
+    assert_raises(Relp::ConnectionClosed) do
+      rc = RelpClient.new('127.0.0.1',15515,['syslog'])
+      badframe = Hash.new
+      badframe['command'] = 'badcommand'
+      rc.frame_write(badframe)
+      #We can't detect that it's closed until we try to write to it again
+      #(delay is required for connection to be closed)
+      sleep 1
+      rc.frame_write(badframe)
+    end
+    assert_equal("Relp error: Relp::InvalidCommand badcommand",logger.pop[:message])
+  end
+
+  test "RelpServer rejects inappropriate commands" do
+    #Need it to close the connection, but not bring down the whole server
+    queue = Queue.new
+    thread = Thread.new { @input.run(queue) }
+
+    logger = Queue.new
+    (@input.instance_eval { @logger }).subscribe(logger)
+
+    assert_raises(Relp::ConnectionClosed) do
+      rc = RelpClient.new('127.0.0.1',15515,['syslog'])
+      badframe = Hash.new
+      badframe['command'] = 'open'#it's not expecting open again
+      rc.frame_write(badframe)
+      #We can't detect that it's closed until we try to write to it again
+      #(but with something other than an open)
+      sleep 1
+      badframe['command'] = 'syslog'
+      rc.frame_write(badframe)
+    end
+    assert_equal("Relp error: Relp::InappropriateCommand open expecting syslog",
+                 logger.pop[:message])
+
+  end
+
+  test "RelpServer refuses to connect if no syslog command available" do
+
+    logger = Queue.new
+    (@input.instance_eval { @logger }).subscribe(logger)
+
+    assert_raises(Relp::RelpError) do
+      queue = Queue.new
+      thread = Thread.new { @input.run(queue) }
+      rc = RelpClient.new('127.0.0.1',15515)
+    end
+ 
+    assert_equal("Relp client incapable of syslog",logger.pop[:message])
+  end
+
+end # testing for LogStash::Inputs::File
+
+#TODO: structured error logging