diff --git a/t/lib-git-daemon.sh b/t/lib-git-daemon.sh
index 394b06b32f..1f22de260a 100644
--- a/t/lib-git-daemon.sh
+++ b/t/lib-git-daemon.sh
@@ -22,7 +22,7 @@ then
 	test_done
 fi
 
-LIB_GIT_DAEMON_PORT=${LIB_GIT_DAEMON_PORT-'8121'}
+LIB_GIT_DAEMON_PORT=${LIB_GIT_DAEMON_PORT-${this_test#t}}
 
 GIT_DAEMON_PID=
 GIT_DAEMON_DOCUMENT_ROOT_PATH="$PWD"/repo
diff --git a/t/t5570-git-daemon.sh b/t/t5570-git-daemon.sh
index e06146835c..6b16379951 100755
--- a/t/t5570-git-daemon.sh
+++ b/t/t5570-git-daemon.sh
@@ -3,7 +3,6 @@
 test_description='test fetching over git protocol'
 . ./test-lib.sh
 
-LIB_GIT_DAEMON_PORT=${LIB_GIT_DAEMON_PORT-5570}
 . "$TEST_DIRECTORY"/lib-git-daemon.sh
 start_git_daemon