diff --git a/hooks.py b/hooks.py
new file mode 100644
index 0000000..f0a6ff9
--- /dev/null
+++ b/hooks.py
@@ -0,0 +1,29 @@
+import cStringIO
+import time
+
+from khepri import hook, get_mac
+
+@hook(r"^pxelinux.cfg/default$")
+def pxelinux_default(path, match, remote):
+    (raddress, rport) = remote
+    mac = get_mac(raddress)
+    if not mac:
+        s = "localboot 0"
+    else:
+        s = """    default menu.c32
+    prompt 0
+
+    menu title "Khepri Boot Menu generated at %s for %s:%i"
+    menu INCLUDE pxelinux.cfg/graphics.conf
+    MENU AUTOBOOT Starting Xen Node in # seconds
+
+    label xen
+        menu label ^Xen Node
+        menu default
+        timeout 80
+        kernel xen/vmlinuz
+        append rootfstype=nfs root=/dev/nfs nfsroot=10.8.1.1:/var/khepri/nfs/xen,v4,rsize=16384,wsize=16384 ip=:::::eth0:dhcp
+""" % (time.strftime("%d/%m/%Y at %H:%M:%S"), raddress, rport)
+    return cStringIO.StringIO(s)
+
+
diff --git a/khepri.py b/khepri.py
new file mode 100755
index 0000000..13c9870
--- /dev/null
+++ b/khepri.py
@@ -0,0 +1,62 @@
+#!/usr/bin/env python
+
+import sys, logging
+import tftpy
+import re
+
+LEASES_FILE = "/var/lib/dhcp/dhcpd.leases"
+
+def get_mac(address):
+    """Gets MAC address from dhcpd leases based on IP address."""
+    f = open(LEASES_FILE,"r")
+    in_lease = False
+    for line in f:
+        line = line.split("#")[0]
+        parts = line.strip().split()
+        if not parts:
+            continue
+        if not in_lease and parts[0] == "lease":
+            in_lease = parts[1]
+            continue
+        field_name = parts[0]
+        if field_name == "hardware" and in_lease == address:
+            return parts[2][:-1]
+        elif field_name == "}":
+            in_lease = False
+    return None
+
+file_hooks = {}
+def hook_dispatcher(path, remote):
+    for pattern, hook in file_hooks.iteritems():
+        match = re.match(pattern, path)
+        if match:
+            data = hook(path, match, remote)
+            if data:
+                return data
+    return None
+
+def hook(pattern, match_mac=None):
+    def decorator(f):
+        def wrapper(path, match, remote):
+            if match_mac:
+                mac = get_mac([0])
+                if match_mac and mac != match_mac:
+                    return None
+
+            return f(path, match, remote)
+        file_hooks[pattern] = wrapper
+        return f
+    return decorator
+
+import hooks
+
+def main():
+    server = tftpy.TftpServer("/var/khepri/tftp-root/", dyn_file_func=hook_dispatcher)
+    try:
+        server.listen("10.8.1.1", 5000)
+    except tftpy.TftpException, err:
+        sys.stderr.write("%s\n" % str(err))
+        sys.exit(1)
+    except KeyboardInterrupt:
+        pass
+
diff --git a/run.py b/run.py
old mode 100755
new mode 100644
index 7b2ba7a..bfa8944
--- a/run.py
+++ b/run.py
@@ -1,53 +1,4 @@
-#!/usr/bin/env python
+import khepri
 
-import sys, logging
-import tftpy
-import re
-import cStringIO
-import time
-
-file_hooks = {}
-def hook_dispatcher(path):
-    for pattern, hook in file_hooks.iteritems():
-        match = re.match(pattern, path)
-        if match:
-            return hook(path, match)
-    return None
-
-def hook(pattern):
-    def decorator(f):
-        file_hooks[pattern] = f
-        return f
-    return decorator
-
-@hook(r"^pxelinux.cfg/default$")
-def pxelinux_default(path, match):
-    s = """default menu.c32
-    prompt 0
-
-    menu title "Khepri Boot Menu generated at %s"
-    menu INCLUDE pxelinux.cfg/graphics.conf
-    MENU AUTOBOOT Starting Xen Node in # seconds
-
-    label xen
-        menu label ^Xen Node
-        menu default
-        timeout 80
-        kernel xen/vmlinuz
-        append rootfstype=nfs root=/dev/nfs nfsroot=10.8.1.1:/var/khepri/nfs/xen,v4,rsize=16384,wsize=16384 ip=:::::eth0:dhcp
-""" % time.strftime("%d/%m/%Y at %H:%M:%S")
-    return cStringIO.StringIO(s)
-
-
-def main():
-    server = tftpy.TftpServer("/var/khepri/tftp-root/", dyn_file_func=hook_dispatcher)
-    try:
-        server.listen("10.8.1.1", 5000)
-    except tftpy.TftpException, err:
-        sys.stderr.write("%s\n" % str(err))
-        sys.exit(1)
-    except KeyboardInterrupt:
-        pass
-
-if __name__ == '__main__':
-    main()
+if __name__ == "__main__":
+    khepri.main()
diff --git a/tftpy/TftpStates.py b/tftpy/TftpStates.py
index 8e4ad1e..da71a37 100644
--- a/tftpy/TftpStates.py
+++ b/tftpy/TftpStates.py
@@ -285,7 +285,7 @@ class TftpStateServerRecvRRQ(TftpServerState):
         elif self.context.dyn_file_func:
             log.debug("No such file %s but using dyn_file_func" % path)
             self.context.fileobj = \
-                self.context.dyn_file_func(self.context.file_to_transfer)
+                self.context.dyn_file_func(self.context.file_to_transfer, (raddress, rport))
 
             if self.context.fileobj is None:
                 log.debug("dyn_file_func returned 'None', treating as "