diff --git a/testing/scripts/diff-canonifier-external b/testing/scripts/diff-canonifier-external
index f4356154e4..37a51fa72f 100755
--- a/testing/scripts/diff-canonifier-external
+++ b/testing/scripts/diff-canonifier-external
@@ -2,10 +2,17 @@
 #
 # Default canonifier used with the trace-based tests in testing/external/*.
 
+addl="cat"
+
+if [ "$1" == "capture_loss.log" ]; then
+    addl="`dirname $0`/diff-remove-fractions"
+fi
+
 `dirname $0`/diff-remove-timestamps \
     | `dirname $0`/diff-remove-uids \
     | `dirname $0`/diff-remove-file-ids \
     | `dirname $0`/diff-remove-x509-names \
     | `dirname $0`/diff-canon-notice-policy \
-    | `dirname $0`/diff-sort
+    | `dirname $0`/diff-sort \
+    | eval $addl
 
diff --git a/testing/scripts/diff-remove-fractions b/testing/scripts/diff-remove-fractions
new file mode 100755
index 0000000000..975157913c
--- /dev/null
+++ b/testing/scripts/diff-remove-fractions
@@ -0,0 +1,6 @@
+#! /usr/bin/env bash
+#
+# Replace fractions of double value (i.e., 3.14 -> 3.x).
+
+sed 's/\.[0-9]\{1,\}/.X/g'
+