diff --git a/cmake/legion.cmake b/cmake/legion.cmake
index 2afb507d3b..adcf5618f8 100644
--- a/cmake/legion.cmake
+++ b/cmake/legion.cmake
@@ -132,6 +132,7 @@ else()
 		  set(Legion_EMBED_GASNet_VERSION "GASNet-2022.3.0" CACHE STRING "GASNet version")
 		  set(Legion_NETWORKS "gasnetex" CACHE STRING "GASNet conduit")
 		  set(GASNet_CONDUIT ${FF_GASNET_CONDUIT})
+		  set(GASNet_SYSTEM ${FF_GASNET_SYSTEM})
 		elseif("${FF_LEGION_NETWORKS}" STREQUAL "ucx")
 		  set(ucx_ROOT ${UCX_PATH}/lib/cmake)
           message(STATUS "Find ucx: ${UCX_PATH}")
diff --git a/config/config.inc b/config/config.inc
index 011fe890fb..b4356bf078 100644
--- a/config/config.inc
+++ b/config/config.inc
@@ -118,6 +118,13 @@ if [ "$FF_LEGION_NETWORKS" = "gasnet" ]; then
     SET_LEGION_NETWORKS+=" -DFF_GASNET_CONDUIT=mpi"
   elif [ "$FF_GASNET_CONDUIT" = "udp" ]; then
     SET_LEGION_NETWORKS+=" -DFF_GASNET_CONDUIT=udp"
+  elif [ "$FF_GASNET_CONDUIT" = "ofi" ]; then
+    SET_LEGION_NETWORKS+=" -DFF_GASNET_CONDUIT=ofi"
+    if [ "$FF_GASNET_SYSTEM" = "slingshot11" ]; then
+      SET_LEGION_NETWORKS+=" -DFF_GASNET_SYSTEM=slingshot11"
+    elif [ "$FF_GASNET_SYSTEM" = "slingshot10" ]; then
+      SET_LEGION_NETWORKS+=" -DFF_GASNET_SYSTEM=slingshot10"
+    fi
   fi
 elif [ "$FF_LEGION_NETWORKS" = "ucx" ]; then
   SET_LEGION_NETWORKS+=" -DFF_LEGION_NETWORKS=ucx"
diff --git a/config/config.linux b/config/config.linux
index 09976cfa03..aae7901494 100755
--- a/config/config.linux
+++ b/config/config.linux
@@ -61,6 +61,9 @@ FF_LEGION_NETWORKS=${FF_LEGION_NETWORKS:-}
 # select GASNET conduit
 FF_GASNET_CONDUIT=${FF_GASNET_CONDUIT:-ibv}
 
+# select GASNET system (usually with OFI conduit)
+FF_GASNET_SYSTEM=${FF_GASNET_SYSTEM:-slingshot11}
+
 # set UCX dir if Legion networks is set to ucx
 UCX_DIR=${UCX_DIR:-""}