diff --git a/Makefile.in b/Makefile.in
index 9e51f65c..f8757683 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -65,7 +65,8 @@ am__aclocal_m4_deps = $(top_srcdir)/m4/acx_pthread.m4 \
 	$(top_srcdir)/m4/ltsugar.m4 $(top_srcdir)/m4/ltversion.m4 \
 	$(top_srcdir)/m4/lt~obsolete.m4 $(top_srcdir)/m4/mbedtls.m4 \
 	$(top_srcdir)/m4/openssl.m4 $(top_srcdir)/m4/polarssl.m4 \
-	$(top_srcdir)/libev/libev.m4 $(top_srcdir)/configure.ac
+	$(top_srcdir)/m4/zlib.m4 $(top_srcdir)/libev/libev.m4 \
+	$(top_srcdir)/configure.ac
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
 	$(ACLOCAL_M4)
 am__CONFIG_DISTCLEAN_FILES = config.status config.cache config.log \
diff --git a/aclocal.m4 b/aclocal.m4
index fd53e841..ceaf07fe 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1173,3 +1173,4 @@ m4_include([m4/lt~obsolete.m4])
 m4_include([m4/mbedtls.m4])
 m4_include([m4/openssl.m4])
 m4_include([m4/polarssl.m4])
+m4_include([m4/zlib.m4])
diff --git a/config.h.in b/config.h.in
index 04437463..693761c8 100644
--- a/config.h.in
+++ b/config.h.in
@@ -245,6 +245,12 @@
 /* Define to 1 if you have the <ws2tcpip.h> header file. */
 #undef HAVE_WS2TCPIP_H
 
+/* have zlib compression support */
+#undef HAVE_ZLIB
+
+/* Define to 1 if you have the <zlib.h> header file. */
+#undef HAVE_ZLIB_H
+
 /* Define to the sub-directory in which libtool stores uninstalled libraries.
    */
 #undef LT_OBJDIR
diff --git a/configure b/configure
index b784d016..545b20b4 100755
--- a/configure
+++ b/configure
@@ -777,6 +777,10 @@ with_gnu_ld
 with_sysroot
 enable_libtool_lock
 with_crypto_library
+enable_zlib
+with_zlib
+with_zlib_include
+with_zlib_lib
 with_openssl
 with_openssl_include
 with_openssl_lib
@@ -1429,6 +1433,7 @@ Optional Features:
   --enable-fast-install[=PKGS]
                           optimize for fast installation [default=yes]
   --disable-libtool-lock  avoid locking (might break parallel builds)
+  --disable-zlib          disable zlib compression support
   --enable-applecc        enable Apple CommonCrypto API support
   --disable-assert        turn off assertions
   --disable-largefile     omit support for large files
@@ -1444,6 +1449,9 @@ Optional Packages:
   --with-crypto-library=library
                           build with the given crypto library,
                           TYPE=openssl|polarssl|mbedtls [default=openssl]
+  --with-zlib=DIR         zlib base directory, or:
+  --with-zlib-include=DIR zlib headers directory
+  --with-zlib-lib=DIR     zlib library directory
   --with-openssl=DIR      OpenSSL base directory, or:
   --with-openssl-include=DIR
                           OpenSSL headers directory (without trailing
@@ -12916,6 +12924,163 @@ fi
 case "${with_crypto_library}" in
   openssl)
 
+  # Check whether --enable-zlib was given.
+if test "${enable_zlib+set}" = set; then :
+  enableval=$enable_zlib;
+fi
+
+  if test "x$enable_zlib" != "xno"; then :
+
+
+$as_echo "#define HAVE_ZLIB 1" >>confdefs.h
+
+
+# Check whether --with-zlib was given.
+if test "${with_zlib+set}" = set; then :
+  withval=$with_zlib; zlib="$withval"
+       CPPFLAGS="$CPPFLAGS -I$withval/include"
+       LDFLAGS="$LDFLAGS -L$withval/lib"
+
+fi
+
+
+
+# Check whether --with-zlib-include was given.
+if test "${with_zlib_include+set}" = set; then :
+  withval=$with_zlib_include; zlib_include="$withval"
+       CPPFLAGS="$CPPFLAGS -I$withval"
+
+fi
+
+
+
+# Check whether --with-zlib-lib was given.
+if test "${with_zlib_lib+set}" = set; then :
+  withval=$with_zlib_lib; zlib_lib="$withval"
+       LDFLAGS="$LDFLAGS -L$withval"
+
+fi
+
+
+    for ac_header in zlib.h
+do :
+  ac_fn_c_check_header_mongrel "$LINENO" "zlib.h" "ac_cv_header_zlib_h" "$ac_includes_default"
+if test "x$ac_cv_header_zlib_h" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_ZLIB_H 1
+_ACEOF
+
+else
+  as_fn_error $? "\"zlib header files not found.\"" "$LINENO" 5; break
+
+fi
+
+done
+
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for compress2 in -lz" >&5
+$as_echo_n "checking for compress2 in -lz... " >&6; }
+if ${ac_cv_lib_z_compress2+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lz  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char compress2 ();
+int
+main ()
+{
+return compress2 ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_z_compress2=yes
+else
+  ac_cv_lib_z_compress2=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_z_compress2" >&5
+$as_echo "$ac_cv_lib_z_compress2" >&6; }
+if test "x$ac_cv_lib_z_compress2" = xyes; then :
+  LIBS="$LIBS -lz"
+else
+  as_fn_error $? "\"zlib libraries not found.\"" "$LINENO" 5
+
+fi
+
+
+fi
+
+
+  case $host_os in
+    *mingw*)
+    ;;
+    *)
+      ac_fn_c_check_func "$LINENO" "dlopen" "ac_cv_func_dlopen"
+if test "x$ac_cv_func_dlopen" = xyes; then :
+
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for dlopen in -ldl" >&5
+$as_echo_n "checking for dlopen in -ldl... " >&6; }
+if ${ac_cv_lib_dl_dlopen+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-ldl  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dlopen ();
+int
+main ()
+{
+return dlopen ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_dl_dlopen=yes
+else
+  ac_cv_lib_dl_dlopen=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dl_dlopen" >&5
+$as_echo "$ac_cv_lib_dl_dlopen" >&6; }
+if test "x$ac_cv_lib_dl_dlopen" = xyes; then :
+  LIBS="$LIBS -ldl"
+else
+  as_fn_error $? "OpenSSL depends on libdl." "$LINENO" 5; break
+
+fi
+
+
+fi
+
+    ;;
+  esac
 
 
 # Check whether --with-openssl was given.
diff --git a/configure.ac b/configure.ac
index 17860729..702a0db0 100755
--- a/configure.ac
+++ b/configure.ac
@@ -59,6 +59,7 @@ AX_TLS([:], [:])
 dnl Checks for crypto library
 case "${with_crypto_library}" in
   openssl)
+    ss_ZLIB
     ss_OPENSSL
     AC_DEFINE([USE_CRYPTO_OPENSSL], [1], [Use OpenSSL library])
     ;;
diff --git a/libcork/Makefile.in b/libcork/Makefile.in
index 570931d0..d3f3a269 100644
--- a/libcork/Makefile.in
+++ b/libcork/Makefile.in
@@ -78,7 +78,8 @@ am__aclocal_m4_deps = $(top_srcdir)/m4/acx_pthread.m4 \
 	$(top_srcdir)/m4/ltsugar.m4 $(top_srcdir)/m4/ltversion.m4 \
 	$(top_srcdir)/m4/lt~obsolete.m4 $(top_srcdir)/m4/mbedtls.m4 \
 	$(top_srcdir)/m4/openssl.m4 $(top_srcdir)/m4/polarssl.m4 \
-	$(top_srcdir)/libev/libev.m4 $(top_srcdir)/configure.ac
+	$(top_srcdir)/m4/zlib.m4 $(top_srcdir)/libev/libev.m4 \
+	$(top_srcdir)/configure.ac
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
 	$(ACLOCAL_M4)
 mkinstalldirs = $(install_sh) -d
diff --git a/libev/Makefile.in b/libev/Makefile.in
index 2b3118a1..eddb6b37 100644
--- a/libev/Makefile.in
+++ b/libev/Makefile.in
@@ -62,7 +62,8 @@ am__aclocal_m4_deps = $(top_srcdir)/m4/acx_pthread.m4 \
 	$(top_srcdir)/m4/ltsugar.m4 $(top_srcdir)/m4/ltversion.m4 \
 	$(top_srcdir)/m4/lt~obsolete.m4 $(top_srcdir)/m4/mbedtls.m4 \
 	$(top_srcdir)/m4/openssl.m4 $(top_srcdir)/m4/polarssl.m4 \
-	$(top_srcdir)/libev/libev.m4 $(top_srcdir)/configure.ac
+	$(top_srcdir)/m4/zlib.m4 $(top_srcdir)/libev/libev.m4 \
+	$(top_srcdir)/configure.ac
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
 	$(ACLOCAL_M4)
 mkinstalldirs = $(install_sh) -d
diff --git a/libipset/Makefile.in b/libipset/Makefile.in
index de289583..29aeb3d4 100644
--- a/libipset/Makefile.in
+++ b/libipset/Makefile.in
@@ -78,7 +78,8 @@ am__aclocal_m4_deps = $(top_srcdir)/m4/acx_pthread.m4 \
 	$(top_srcdir)/m4/ltsugar.m4 $(top_srcdir)/m4/ltversion.m4 \
 	$(top_srcdir)/m4/lt~obsolete.m4 $(top_srcdir)/m4/mbedtls.m4 \
 	$(top_srcdir)/m4/openssl.m4 $(top_srcdir)/m4/polarssl.m4 \
-	$(top_srcdir)/libev/libev.m4 $(top_srcdir)/configure.ac
+	$(top_srcdir)/m4/zlib.m4 $(top_srcdir)/libev/libev.m4 \
+	$(top_srcdir)/configure.ac
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
 	$(ACLOCAL_M4)
 mkinstalldirs = $(install_sh) -d
diff --git a/libudns/Makefile.in b/libudns/Makefile.in
index 24517277..7753b318 100644
--- a/libudns/Makefile.in
+++ b/libudns/Makefile.in
@@ -78,7 +78,8 @@ am__aclocal_m4_deps = $(top_srcdir)/m4/acx_pthread.m4 \
 	$(top_srcdir)/m4/ltsugar.m4 $(top_srcdir)/m4/ltversion.m4 \
 	$(top_srcdir)/m4/lt~obsolete.m4 $(top_srcdir)/m4/mbedtls.m4 \
 	$(top_srcdir)/m4/openssl.m4 $(top_srcdir)/m4/polarssl.m4 \
-	$(top_srcdir)/libev/libev.m4 $(top_srcdir)/configure.ac
+	$(top_srcdir)/m4/zlib.m4 $(top_srcdir)/libev/libev.m4 \
+	$(top_srcdir)/configure.ac
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
 	$(ACLOCAL_M4)
 mkinstalldirs = $(install_sh) -d
diff --git a/m4/openssl.m4 b/m4/openssl.m4
index 2cfd34ad..c47e94b0 100644
--- a/m4/openssl.m4
+++ b/m4/openssl.m4
@@ -2,6 +2,19 @@ dnl Check to find the OpenSSL headers/libraries
 
 AC_DEFUN([ss_OPENSSL],
 [
+  case $host_os in
+    *mingw*)
+    ;;
+    *)
+      AC_CHECK_FUNC(dlopen,
+        [],
+        [AC_CHECK_LIB(dl, dlopen,
+          [LIBS="$LIBS -ldl"],
+          [AC_MSG_ERROR([OpenSSL depends on libdl.]); break]
+        )]
+      )
+    ;;
+  esac
 
   AC_ARG_WITH(openssl,
     AS_HELP_STRING([--with-openssl=DIR], [OpenSSL base directory, or:]),
diff --git a/m4/zlib.m4 b/m4/zlib.m4
new file mode 100644
index 00000000..13082862
--- /dev/null
+++ b/m4/zlib.m4
@@ -0,0 +1,38 @@
+dnl Check to find the zlib headers/libraries
+
+AC_DEFUN([ss_ZLIB],
+[
+  AC_ARG_ENABLE([zlib],
+    AS_HELP_STRING([--disable-zlib], [disable zlib compression support]))
+  AS_IF([test "x$enable_zlib" != "xno"], [
+  AC_DEFINE(HAVE_ZLIB, 1, [have zlib compression support])
+    AC_ARG_WITH(zlib,
+      AS_HELP_STRING([--with-zlib=DIR], [zlib base directory, or:]),
+      [zlib="$withval"
+       CPPFLAGS="$CPPFLAGS -I$withval/include"
+       LDFLAGS="$LDFLAGS -L$withval/lib"]
+    )
+
+    AC_ARG_WITH(zlib-include,
+      AS_HELP_STRING([--with-zlib-include=DIR], [zlib headers directory]),
+      [zlib_include="$withval"
+       CPPFLAGS="$CPPFLAGS -I$withval"]
+    )
+
+    AC_ARG_WITH(zlib-lib,
+      AS_HELP_STRING([--with-zlib-lib=DIR], [zlib library directory]),
+      [zlib_lib="$withval"
+       LDFLAGS="$LDFLAGS -L$withval"]
+    )
+
+    AC_CHECK_HEADERS(zlib.h,
+      [],
+      [AC_MSG_ERROR("zlib header files not found."); break]
+    )
+
+    AC_CHECK_LIB(z, compress2,
+      [LIBS="$LIBS -lz"],
+      [AC_MSG_ERROR("zlib libraries not found.")]
+    )
+  ])
+])
diff --git a/src/Makefile.in b/src/Makefile.in
index 94af3db0..cf9fdab2 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -69,7 +69,8 @@ am__aclocal_m4_deps = $(top_srcdir)/m4/acx_pthread.m4 \
 	$(top_srcdir)/m4/ltsugar.m4 $(top_srcdir)/m4/ltversion.m4 \
 	$(top_srcdir)/m4/lt~obsolete.m4 $(top_srcdir)/m4/mbedtls.m4 \
 	$(top_srcdir)/m4/openssl.m4 $(top_srcdir)/m4/polarssl.m4 \
-	$(top_srcdir)/libev/libev.m4 $(top_srcdir)/configure.ac
+	$(top_srcdir)/m4/zlib.m4 $(top_srcdir)/libev/libev.m4 \
+	$(top_srcdir)/configure.ac
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
 	$(ACLOCAL_M4)
 mkinstalldirs = $(install_sh) -d