diff --git a/test/client.test.js b/test/client.test.js
index f44c6f7..d3b28a9 100644
--- a/test/client.test.js
+++ b/test/client.test.js
@@ -1,6 +1,7 @@
 'use strict'
 
 const util = require('util')
+const assert = require('assert')
 const tap = require('tap')
 const uuid = require('uuid')
 const vasync = require('vasync')
@@ -57,6 +58,12 @@ tap.beforeEach((done, t) => {
     return next()
   })
 
+  server.modifyDN('cn=issue-480', function (req, res, next) {
+    assert(req.newRdn.toString().length > 132)
+    res.end()
+    return next()
+  })
+
   server.search('dc=slow', function (req, res, next) {
     res.send({
       dn: 'dc=slow',
@@ -533,6 +540,15 @@ tap.test('modify DN new superior', function (t) {
   })
 })
 
+tap.test('modify DN excessive length (GH-480)', function (t) {
+  t.context.client.modifyDN('cn=issue-480', 'cn=a292979f2c86d513d48bbb9786b564b3c5228146e5ba46f404724e322544a7304a2b1049168803a5485e2d57a544c6a0d860af91330acb77e5907a9e601ad1227e80e0dc50abe963b47a004f2c90f570450d0e920d15436fdc771e3bdac0487a9735473ed3a79361d1778d7e53a7fb0e5f01f97a75ef05837d1d5496fc86968ff47fcb64', function (err, res) {
+    t.error(err)
+    t.ok(res)
+    t.equal(res.status, 0)
+    t.end()
+  })
+})
+
 tap.test('search basic', function (t) {
   t.context.client.search('cn=test, ' + SUFFIX, '(objectclass=*)', function (err, res) {
     t.error(err)