diff --git a/server/libs/dnser.rb b/server/libs/dnser.rb
index 0af84aea..ee57d27d 100644
--- a/server/libs/dnser.rb
+++ b/server/libs/dnser.rb
@@ -837,13 +837,13 @@ def initialize(host, port, cache=false)
   # This method returns immediately, but spawns a background thread. The thread
   # will recveive and parse DNS packets, create a transaction, and pass it to
   # the caller's block.
-  def on_request()
+  def on_request(&block)
     @thread = Thread.new() do |t|
       begin
         loop do
           data = @s.recvfrom(65536)
-          
-          begin   
+
+          begin
             # Data is an array where the first element is the actual data, and the second is the host/port
             request = DNSer::Packet.parse(data[0])
 
@@ -869,7 +869,7 @@ def on_request()
 
             if(!transaction.sent)
               begin
-                proc.call(transaction)
+                block.call(transaction)
               rescue StandardError => e
                 puts("Caught an error: #{e}")
                 puts(e.backtrace())
@@ -912,7 +912,7 @@ def wait()
   # Send out a query, asynchronously. This immediately returns, then, when the
   # query is finished, the callback block is called with a DNSer::Packet that
   # represents the response (or nil, if there was a timeout).
-  def DNSer.query(hostname, params = {})
+  def DNSer.query(hostname, params = {}, &block)
     server   = params[:server]   || "8.8.8.8"
     port     = params[:port]     || 53
     type     = params[:type]     || DNSer::Packet::TYPE_A
@@ -930,10 +930,10 @@ def DNSer.query(hostname, params = {})
 
         timeout(timeout) do
           response = s.recv(65536)
-          proc.call(DNSer::Packet.parse(response))
+          block.call(DNSer::Packet.parse(response))
         end
       rescue Timeout::Error
-        proc.call(nil)
+        block.call(nil)
       rescue Exception => e
         puts("There was an exception sending a query for #{hostname} to #{server}:#{port}: #{e}")
       ensure
diff --git a/server/libs/settings.rb b/server/libs/settings.rb
index 64882382..7fb5dafe 100644
--- a/server/libs/settings.rb
+++ b/server/libs/settings.rb
@@ -157,13 +157,13 @@ def each_setting()
 
   # Create a new setting, or replace an old one. This must be done before a
   # setting is used.
-  def create(name, type, default_value, docs)
+  def create(name, type, default_value, docs, &block)
     name = name.to_s()
 
     @settings[name] = @settings[name] || {}
 
     @settings[name][:type]    = type
-    @settings[name][:watcher] = proc
+    @settings[name][:watcher] = block
     @settings[name][:docs]    = docs
     @settings[name][:default] = @@mutators[type].call(default_value.to_s())
 
diff --git a/server/libs/swindow.rb b/server/libs/swindow.rb
index 3095a48a..9292c924 100644
--- a/server/libs/swindow.rb
+++ b/server/libs/swindow.rb
@@ -60,14 +60,14 @@ class SWindow
 
   # This function will trap the TSTP signal (suspend, ctrl-z) and, if possible,
   # activate the parent window.
-  def SWindow._catch_suspend()
+  def SWindow._catch_suspend(&block)
     orig_suspend = Signal.trap("TSTP") do
       if(@@active)
         @@active.deactivate()
       end
     end
 
-    proc.call()
+    block.call()
 
     Signal.trap("TSTP", orig_suspend)
   end
@@ -182,8 +182,8 @@ def children()
 
   # Set the on_input callback - the function that will be called when input is
   # received. Very important!
-  def on_input()
-    @callback = proc
+  def on_input(&block)
+    @callback = block
   end
 
   def with(params = {})
diff --git a/server/tunnel_drivers/driver_dns.rb b/server/tunnel_drivers/driver_dns.rb
index f4e778e6..96023603 100644
--- a/server/tunnel_drivers/driver_dns.rb
+++ b/server/tunnel_drivers/driver_dns.rb
@@ -313,7 +313,7 @@ def initialize(parent_window, host, port, domains, cache)
         end
 
         # Get the response
-        response = proc.call(name, max_length)
+        response = yield(name, max_length)
 
         if(response.length > max_length)
           raise(DnscatException, "The handler returned too much data! This shouldn't happen, please report. (max = #{max_length}, returned = #{response.length}")