diff --git a/Makefile.in b/Makefile.in
index c6aa3232e..a50c55941 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -110,7 +110,12 @@ OBJS = main.o nmap.o targets.o tcpip.o nmap_error.o utils.o idle_scan.o osscan.o
 # large for field of 2 bytes". Disable debugging for this one file.
 FPModel.o: CXXFLAGS += -g0
 
-all: @LUA_BUILD@ @LIBLINEAR_BUILD@ @PCAP_BUILD@ @PCRE_BUILD@ @DNET_BUILD@ @NBASE_BUILD@ @NSOCK_BUILD@ @NCAT_BUILD@ netutil_build
+warn-svn-move:
+	@echo "Nmap's Subversion repository has moved. Run this command:"
+	@echo "svn switch --relocate svn://svn.insecure.org/nmap https://svn.nmap.org/nmap"
+	false
+
+all: warn-svn-move @LUA_BUILD@ @LIBLINEAR_BUILD@ @PCAP_BUILD@ @PCRE_BUILD@ @DNET_BUILD@ @NBASE_BUILD@ @NSOCK_BUILD@ @NCAT_BUILD@ netutil_build
 	$(MAKE) $(TARGET) $(BUILDZENMAP) $(BUILDNDIFF) $(BUILDNPING)
 
 $(TARGET): @LUA_DEPENDS@ @LIBLINEAR_DEPENDS@ @PCAP_DEPENDS@ @PCRE_DEPENDS@ @DNET_DEPENDS@ $(NBASEDIR)/libnbase.a $(NSOCKDIR)/src/libnsock.a libnetutil/libnetutil.a $(OBJS)
diff --git a/README-SVN b/README-SVN
new file mode 100644
index 000000000..eafdc02c3
--- /dev/null
+++ b/README-SVN
@@ -0,0 +1,11 @@
+After r27443 the Nmap Subversion repository was moved. To update your
+working directory, run this command:
+
+~/nmap$ svn switch --relocate svn://svn.insecure.org/nmap https://svn.nmap.org/nmap
+
+If you get errors in the nbase, ncat, nping, nsock, and zenmap
+directories after updating, then delete those directories and update
+again.
+
+~/nmap$ rm -rf nbase ncat nping nsock zenmap
+~/nmap$ svn update