diff --git a/configure b/configure
index 790aa2b61a28cf34b01bc2c27950b1cfabd632a1..994ee41c473fd10b1bd186b7d0b863abb1fe6282 100755
--- a/configure
+++ b/configure
@@ -866,6 +866,7 @@ fi
 
 
 
+
 
 
 #
@@ -908,6 +909,7 @@ IPBASE=10
 SFSSUPPORT=1
 PLABSUPPORT=0
 PLAB_ROOTBALL="plabroot-8.tgz"
+PLAB_SLICEPREFIX="emulab"
 TBLOGFACIL="local5"
 
 #
@@ -1292,7 +1294,7 @@ fi
 # SVR4 /usr/ucb/install, which tries to use the nonexistent group "staff"
 # ./install, which can be erroneously created by make from ./install.sh.
 echo $ac_n "checking for a BSD compatible install""... $ac_c" 1>&6
-echo "configure:1296: checking for a BSD compatible install" >&5
+echo "configure:1298: checking for a BSD compatible install" >&5
 if test -z "$INSTALL"; then
 if eval "test \"`echo '$''{'ac_cv_path_install'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
@@ -1639,6 +1641,7 @@ s%@SFSSUPPORT@%$SFSSUPPORT%g
 s%@PLABSUPPORT@%$PLABSUPPORT%g
 s%@TBLOGFACIL@%$TBLOGFACIL%g
 s%@PLAB_ROOTBALL@%$PLAB_ROOTBALL%g
+s%@PLAB_SLICEPREFIX@%$PLAB_SLICEPREFIX%g
 s%@TBOPSEMAIL@%$TBOPSEMAIL%g
 s%@TBOPSEMAIL_NOSLASH@%$TBOPSEMAIL_NOSLASH%g
 s%@TBLOGSEMAIL@%$TBLOGSEMAIL%g
diff --git a/configure.in b/configure.in
index 0a4e588e5d8579bf09c2a303ab122b794d628583..9da5c9149f98dea8646c6c912604d51b60e88e09 100755
--- a/configure.in
+++ b/configure.in
@@ -59,6 +59,7 @@ AC_SUBST(SFSSUPPORT)
 AC_SUBST(PLABSUPPORT)
 AC_SUBST(TBLOGFACIL)
 AC_SUBST(PLAB_ROOTBALL)
+AC_SUBST(PLAB_SLICEPREFIX)
 
 #
 # Offer both versions of the email addresses that have the @ escaped
@@ -100,6 +101,7 @@ IPBASE=10
 SFSSUPPORT=1
 PLABSUPPORT=0
 PLAB_ROOTBALL="plabroot-8.tgz"
+PLAB_SLICEPREFIX="emulab"
 TBLOGFACIL="local5"
 
 #
diff --git a/defs-barb-mini b/defs-barb-mini
index b0e83cb98cad75aa13a6d0f931d94aa71e45a8ed..ac3e2b7a8add1e15674e08582ef7c96d0e2a0aff 100644
--- a/defs-barb-mini
+++ b/defs-barb-mini
@@ -27,3 +27,4 @@ WWW=www.mini.emulab.net/~barb/www
 TBCOOKIESUFFIX=-mini
 THISHOMEBASE=Mini.Emulab.Net
 FS_WITH_QUOTAS="/z"
+PLAB_SLICEPREFIX=emulab_mini
diff --git a/defs-default b/defs-default
index 48dff10d5424f445ca40aab3bdb173e6dae6f64a..875e9e3237315e82a73df5be6ce9fc16366fc1a1 100644
--- a/defs-default
+++ b/defs-default
@@ -33,3 +33,4 @@ WWWHOST=www.emulab.net
 TBMAINSITE=1
 THISHOMEBASE=Emulab.Net
 PLABSUPPORT=1
+PLAB_SLICEPREFIX=emulab
diff --git a/defs-kwebb-emulab b/defs-kwebb-emulab
index 972d1e062107c7e853987596a0b684673ea39ce3..4a11917c3d628d9ebfa0035e3110c660f7fc6d97 100644
--- a/defs-kwebb-emulab
+++ b/defs-kwebb-emulab
@@ -2,10 +2,10 @@
 # This is the definitions file for Kirk on Emulab.Net.
 #
 TBDBNAME=tbdb
-TBOPSEMAIL=kwebb@cs.utah.edu
-TBLOGSEMAIL=kwebb@cs.utah.edu
-TBWWWEMAIL=kwebb@cs.utah.edu
-TBAUDITEMAIL=kwebb@cs.utah.edu
+TBOPSEMAIL=kwebb@flux.utah.edu
+TBLOGSEMAIL=kwebb@flux.utah.edu
+TBWWWEMAIL=kwebb@flux.utah.edu
+TBAUDITEMAIL=kwebb@flux.utah.edu
 BOSSNODE=boss.emulab.net
 USERNODE=users.emulab.net
 FSNODE=fs.emulab.net
@@ -14,9 +14,9 @@ DELAYCAPACITY=2
 FSDIR_GROUPS=/q/groups
 FSDIR_PROJ=/q/proj
 FSDIR_USERS=/users
-TBSTATEDEMAIL=kwebb@cs.utah.edu
-TBTESTSUITEEMAIL=kwebb@cs.utah.edu
+TBSTATEDEMAIL=kwebb@flux.utah.edu
+TBTESTSUITEEMAIL=kwebb@flux.utah.edu
 WWWHOST=www.emulab.net
-WWW=www.emulab.net/~kwebb/www
+WWW=www.emulab.net/dev/kwebb
 FS_WITH_QUOTAS="/q /users"
 PLABSUPPORT=1
diff --git a/defs-mini b/defs-mini
index af954cf90bf4ed738c155ad2930e76a20844cc12..a0c21191b05bc28c0caba05277f7388acac6a61f 100644
--- a/defs-mini
+++ b/defs-mini
@@ -30,3 +30,4 @@ SFSSUPPORT=0
 WWWHOST=www.mini.emulab.net
 TBCOOKIESUFFIX=-mini
 THISHOMEBASE=Mini.Emulab.Net
+PLAB_SLICEPREFIX=emulab_mini
diff --git a/defs-newbold-mini b/defs-newbold-mini
index 2223e9b3ec81ae14528f87da3128e7b966cfe540..3bb5f400ee109781aeeef6fafadd72bff42708d5 100644
--- a/defs-newbold-mini
+++ b/defs-newbold-mini
@@ -25,3 +25,4 @@ TBCOOKIESUFFIX=-mini
 THISHOMEBASE=Mini.Emulab.Net
 TBAUTHTIMEOUT=216000
 FS_WITH_QUOTAS="/z"
+PLAB_SLICEPREFIX=emulab_mini
diff --git a/defs-ricci-mini b/defs-ricci-mini
index 049b3c69aa009a9989e9a83550a74b33bda792e9..1a12a70cc7bfb8d044bdc7c789d628e2129e598d 100644
--- a/defs-ricci-mini
+++ b/defs-ricci-mini
@@ -30,3 +30,4 @@ WWW=www.mini.emulab.net/~ricci/www
 TBCOOKIESUFFIX=-mini
 THISHOMEBASE=Mini.Emulab.Net
 FS_WITH_QUOTAS="/z"
+PLAB_SLICEPREFIX=emulab_mini
diff --git a/defs-shash-mini b/defs-shash-mini
index 9cc612cd0d511719fb00e8ed7d7881dc1495b77f..b46b95d45a6b10b4adabeccc89910f1df106bc52 100644
--- a/defs-shash-mini
+++ b/defs-shash-mini
@@ -30,3 +30,4 @@ WWW=www.mini.emulab.net/dev/shash
 TBCOOKIESUFFIX=-mini
 THISHOMEBASE=Mini-Shash.Emulab.Net
 FS_WITH_QUOTAS="/z"
+PLAB_SLICEPREFIX=emulab_mini
diff --git a/defs-stoller-mini b/defs-stoller-mini
index 6b478698189c25a3a5e5fab101942043191e5c5b..2437edf0ec327436105a2f23c74691167fd0a200 100644
--- a/defs-stoller-mini
+++ b/defs-stoller-mini
@@ -28,3 +28,4 @@ WWW=www.mini.emulab.net/~stoller/www
 TBCOOKIESUFFIX=-mini
 THISHOMEBASE=Stoller.Mini.Emulab.Net
 FS_WITH_QUOTAS="/z"
+PLAB_SLICEPREFIX=emulab_mini
diff --git a/tbsetup/plab/libplab.py.in b/tbsetup/plab/libplab.py.in
index 8375adbd9b1de34c5070252133bf843e1c57e417..c64c352d2cbd080a43069a1198b4c131ee7faa3c 100644
--- a/tbsetup/plab/libplab.py.in
+++ b/tbsetup/plab/libplab.py.in
@@ -68,6 +68,7 @@ HTTP_PATH = "/" # ensure this ends in a slash
 ROOTBALL_HTTP_URLPATH = HTTPD_SITE + HTTPD_PORT + HTTP_PATH
 
 DEF_ROOTBALL_NAME = "@PLAB_ROOTBALL@"
+SLICEPREFIX = "@PLAB_SLICEPREFIX@"
 
 #
 # How many seconds to sleep between failures and how many times to try
@@ -635,7 +636,7 @@ class Plab:
         # Add new nodes
         toadd = []  # List of IP's
         for ip in avail:
-            if not known.has_key(ip):
+            if not known.has_key(ip) and ip not in toadd:
                 if len(ALLOWED_NODES) and not ip in ALLOWED_NODES:
                     if verbose:
                         print "Skipping %s because it's not in the allowed" \
@@ -1024,7 +1025,7 @@ class Slice:
         if not len(res):
             raise RuntimeError, "Didn't get any results while looking for idx"
         eindex = res[0][0]
-        self.slicename = "emulab_%s" % eindex
+        self.slicename = "%s_%s" % (SLICEPREFIX, eindex)
         print "Creating Plab slice %s." % self.slicename
         self.privkey, self.pubkey = self.__genKeypair()
         try: