diff --git a/src/H5FDmirror.h b/src/H5FDmirror.h
index 304f1e5a3f8..95ce936594d 100644
--- a/src/H5FDmirror.h
+++ b/src/H5FDmirror.h
@@ -35,7 +35,7 @@
 #define H5FD_MIRROR_CURR_FAPL_T_VERSION 1
 
 /** Max size of the remote_ip array in H5FD_mirror_fapl_t */
-#define H5FD_MIRROR_MAX_IP_LEN 32
+#define H5FD_MIRROR_MAX_IP_LEN 45 /* Max size of an IPv4-mapped IPv6 address */
 
 /**
  *\struct H5FD_mirror_fapl_t