diff --git a/linkcheck/checker/ftpurl.py b/linkcheck/checker/ftpurl.py
index cf776655..e79c08a8 100644
--- a/linkcheck/checker/ftpurl.py
+++ b/linkcheck/checker/ftpurl.py
@@ -18,7 +18,7 @@ Handle FTP links.
 """
 
 import ftplib
-from io import StringIO
+from io import BytesIO
 
 from .. import log, LOG_CHECK, LinkCheckerError, mimeutil
 from . import internpaturl, get_index_html
@@ -179,12 +179,12 @@ class FtpUrl(internpaturl.InternPatternUrl):
         else:
             # download file in BINARY mode
             ftpcmd = f"RETR {self.filename}"
-            buf = StringIO()
+            buf = BytesIO()
 
             def stor_data(s):
                 """Helper method storing given data"""
                 # limit the download size
-                if (buf.tell() + len(s)) > self.max_size:
+                if (buf.tell() + len(s)) > self.aggregate.config["maxfilesizedownload"]:
                     raise LinkCheckerError(_("FTP file size too large"))
                 buf.write(s)
 
diff --git a/tests/checker/test_ftp.py b/tests/checker/test_ftp.py
index da692007..6f597f7a 100644
--- a/tests/checker/test_ftp.py
+++ b/tests/checker/test_ftp.py
@@ -33,6 +33,7 @@ class TestFtp(FtpServerTest):
             "real url %s" % url,
             "valid",
         ]
+        self.direct(url, resultlines)
         # ftp use/password
         user = "anonymous"
         passwd = "Ftp"