diff --git a/doc/changelog.txt b/doc/changelog.txt
index 582edb91..a0a23d64 100644
--- a/doc/changelog.txt
+++ b/doc/changelog.txt
@@ -4,6 +4,8 @@ Fixes:
 - checking: Catch any errors initializing the MIME database.
   Closes: SF bug #3528450
 - checking: Fix writing temporary files.
+- checking: Properly handle URLs with user/password information.
+  Closes: SF bug #3529812
 
 Changes:
 - checking: Ignore URLs from local PHP files with execution
@@ -17,7 +19,8 @@ Changes:
 Features:
 - installation: Support RPM building with cx_Freeze.
 - installation: Added .desktop files for POSIX systems.
-- checking: Allow writing of a memory dump file.
+- checking: Allow writing of a memory dump file to debug memory
+  problems.
 
 
 7.8 "Gangster Exchange" (released 12.5.2012)
diff --git a/linkcheck/checker/ftpurl.py b/linkcheck/checker/ftpurl.py
index ae6287b2..b51fb93a 100644
--- a/linkcheck/checker/ftpurl.py
+++ b/linkcheck/checker/ftpurl.py
@@ -1,5 +1,5 @@
 # -*- coding: iso-8859-1 -*-
-# Copyright (C) 2000-2011 Bastian Kleineidam
+# Copyright (C) 2000-2012 Bastian Kleineidam
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -19,7 +19,6 @@ Handle FTP links.
 """
 
 import ftplib
-import urllib
 from cStringIO import StringIO
 
 from .. import log, LOG_CHECK, LinkCheckerError, fileutil
@@ -71,34 +70,24 @@ class FtpUrl (internpaturl.InternPatternUrl, proxysupport.ProxySupport):
         self.files = []
         return None
 
-    def get_user_password (self):
-        """
-        Get credentials to use for login.
-        """
-        if self.userinfo:
-            return urllib.splitpasswd(self.userinfo)
-        return super(FtpUrl, self).get_user_password()
-
     def login (self):
         """
         Log into ftp server and check the welcome message.
         """
         # ready to connect
         _user, _password = self.get_user_password()
-        host = self.urlparts[1]
-        key = ("ftp", host, _user, _password)
+        key = ("ftp", self.host, self.port, _user, _password)
         conn = self.aggregate.connections.get(key)
         if conn is not None and conn.sock is not None:
             # reuse cached FTP connection
             self.url_connection = conn
             return
-        self.aggregate.connections.wait_for_host(host)
+        self.aggregate.connections.wait_for_host(self.host)
         try:
             self.url_connection = ftplib.FTP()
             if log.is_debug(LOG_CHECK):
                 self.url_connection.set_debuglevel(1)
-            host, port = proxysupport.parse_host_port(host)
-            self.url_connection.connect(host, port)
+            self.url_connection.connect(self.host, self.port)
             if _user is None:
                 self.url_connection.login()
             elif _password is None:
diff --git a/linkcheck/checker/httpurl.py b/linkcheck/checker/httpurl.py
index 9fe9aab6..784fcc56 100644
--- a/linkcheck/checker/httpurl.py
+++ b/linkcheck/checker/httpurl.py
@@ -132,6 +132,7 @@ class HttpUrl (internpaturl.InternPatternUrl, proxysupport.ProxySupport):
         """
         # set the proxy, so a 407 status after this is an error
         self.set_proxy(self.aggregate.config["proxy"].get(self.scheme))
+        self.construct_auth()
         # check robots.txt
         if not self.allows_robots(self.url):
             # remove all previously stored results
@@ -249,11 +250,7 @@ class HttpUrl (internpaturl.InternPatternUrl, proxysupport.ProxySupport):
                        tag=WARN_HTTP_AUTH_UNKNOWN)
                     return
                 if not self.auth:
-                    _user, _password = self.get_user_password()
-                    self.auth = "Basic " + \
-                        httputil.encode_base64("%s:%s" % (_user, _password))
-                    log.debug(LOG_CHECK,
-                        "Authentication %s/%s", _user, _password)
+                    self.construct_auth()
                     continue
             if (self.headers and self.method == "HEAD" and
                 self.method_get_allowed):
@@ -275,6 +272,18 @@ class HttpUrl (internpaturl.InternPatternUrl, proxysupport.ProxySupport):
         self.aliases = []
         self.fallback_get = True
 
+    def construct_auth (self):
+        """Construct HTTP Basic authentication credentials if there
+        is user/password information available. Does not overwrite if
+        credentials have already been constructed."""
+        if self.auth:
+            return
+        _user, _password = self.get_user_password()
+        if _user is not None and _password is not None:
+            credentials = httputil.encode_base64("%s:%s" % (_user, _password))
+            self.auth = "Basic " + credentials
+            log.debug(LOG_CHECK, "Using basic authentication")
+
     def get_content_type (self):
         """Return content MIME type or empty string."""
         if self.content_type is None:
@@ -308,6 +317,7 @@ class HttpUrl (internpaturl.InternPatternUrl, proxysupport.ProxySupport):
         self.add_info(_("Redirected to `%(url)s'.") % {'url': newurl})
         # norm base url - can raise UnicodeError from url.idna_encode()
         redirected, is_idn = urlbase.url_norm(newurl)
+        # XXX recalculate authentication information when available
         log.debug(LOG_CHECK, "Norm redirected to %r", redirected)
         urlparts = strformat.url_unicode_split(redirected)
         if not self.check_redirection_scheme(redirected, urlparts, set_result):
@@ -354,6 +364,7 @@ class HttpUrl (internpaturl.InternPatternUrl, proxysupport.ProxySupport):
 
     def check_redirection_domain (self, redirected, urlparts, set_result, response):
         """Return True if redirection domain is ok, else False."""
+        # XXX does not support user:pass@netloc format
         if urlparts[1] != self.urlparts[1]:
             # URL domain changed
             if self.recursion_level == 0 and urlparts[0] in ('http', 'https'):
@@ -524,11 +535,8 @@ class HttpUrl (internpaturl.InternPatternUrl, proxysupport.ProxySupport):
                                        skip_accept_encoding=True)
         # be sure to use the original host as header even for proxies
         self.url_connection.putheader("Host", self.urlparts[1])
-        # userinfo is from http://user@pass:host/
-        if self.userinfo:
-            self.url_connection.putheader("Authorization", self.userinfo)
-        # auth is the -u and -p configuration options
-        elif self.auth:
+        if self.auth:
+            # HTTP authorization
             self.url_connection.putheader("Authorization", self.auth)
         if self.proxyauth:
             self.url_connection.putheader("Proxy-Authorization",
diff --git a/linkcheck/checker/telneturl.py b/linkcheck/checker/telneturl.py
index e8abf094..b0449f04 100644
--- a/linkcheck/checker/telneturl.py
+++ b/linkcheck/checker/telneturl.py
@@ -1,5 +1,5 @@
 # -*- coding: iso-8859-1 -*-
-# Copyright (C) 2000-2009 Bastian Kleineidam
+# Copyright (C) 2000-2012 Bastian Kleineidam
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -19,7 +19,6 @@ Handle telnet: links.
 """
 
 import telnetlib
-import urllib
 from . import urlbase
 from .. import log, LOG_CHECK
 
@@ -38,11 +37,8 @@ class TelnetUrl (urlbase.UrlBase):
         # default port
         if self.port is None:
             self.port = 23
-        # split user/pass
-        if self.userinfo:
-            self.user, self.password = urllib.splitpasswd(self.userinfo)
-        else:
-            self.user, self.password = self.get_user_password()
+        # set user/pass
+        self.user, self.password = self.get_user_password()
 
     def local_check (self):
         """
diff --git a/linkcheck/checker/urlbase.py b/linkcheck/checker/urlbase.py
index 3f0157de..112dfed4 100644
--- a/linkcheck/checker/urlbase.py
+++ b/linkcheck/checker/urlbase.py
@@ -929,6 +929,9 @@ class UrlBase (object):
         """Get tuple (user, password) from configured authentication.
         Both user and password can be None.
         """
+        if self.userinfo:
+            # URL itself has authentication info
+            return urllib.splitpasswd(self.userinfo)
         return self.aggregate.config.get_user_password(self.url)
 
     def parse_html (self):
diff --git a/linkcheck/url.py b/linkcheck/url.py
index 555278a9..797eef86 100644
--- a/linkcheck/url.py
+++ b/linkcheck/url.py
@@ -233,42 +233,47 @@ def idna_encode (host):
 
 def url_fix_host (urlparts):
     """Unquote and fix hostname. Returns is_idn."""
-    urlparts[1], is_idn = idna_encode(urllib.unquote(urlparts[1]).lower())
+    if not urlparts[1]:
+        urlparts[2] = urllib.unquote(urlparts[2])
+        return False
+    userpass, netloc = urllib.splituser(urlparts[1])
+    if userpass:
+        userpass = urllib.unquote(userpass)
+    netloc, is_idn = idna_encode(urllib.unquote(netloc).lower())
     # a leading backslash in path causes urlsplit() to add the
     # path components up to the first slash to host
     # try to find this case...
-    i = urlparts[1].find("\\")
+    i = netloc.find("\\")
     if i != -1:
         # ...and fix it by prepending the misplaced components to the path
-        comps = urlparts[1][i:] # note: still has leading backslash
+        comps = netloc[i:] # note: still has leading backslash
         if not urlparts[2] or urlparts[2] == '/':
             urlparts[2] = comps
         else:
             urlparts[2] = "%s%s" % (comps, urllib.unquote(urlparts[2]))
-        urlparts[1] = urlparts[1][:i]
+        netloc = netloc[:i]
     else:
         # a leading ? in path causes urlsplit() to add the query to the
         # host name
-        i = urlparts[1].find("?")
+        i = netloc.find("?")
         if i != -1:
-            urlparts[1], urlparts[3] = urlparts[1].split('?', 1)
+            netloc, urlparts[3] = netloc.split('?', 1)
         # path
         urlparts[2] = urllib.unquote(urlparts[2])
-    if urlparts[1]:
-        userpass, host = urllib.splituser(urlparts[1])
-        if userpass:
-            # append AT for easy concatenation
-            userpass += "@"
-        else:
-            userpass = ""
-        if urlparts[0] in default_ports:
-            dport = default_ports[urlparts[0]]
-            host, port = splitport(host, port=dport)
-            if host.endswith("."):
-                host = host[:-1]
-            if port != dport:
-                host = "%s:%d" % (host, port)
-        urlparts[1] = userpass+host
+    if userpass:
+        # append AT for easy concatenation
+        userpass += "@"
+    else:
+        userpass = ""
+    if urlparts[0] in default_ports:
+        dport = default_ports[urlparts[0]]
+        host, port = splitport(netloc, port=dport)
+        if host.endswith("."):
+            host = host[:-1]
+        if port != dport:
+            host = "%s:%d" % (host, port)
+        netloc = host
+    urlparts[1] = userpass+netloc
     return is_idn
 
 
diff --git a/tests/checker/test_ftp.py b/tests/checker/test_ftp.py
index f818c423..8c4beffb 100644
--- a/tests/checker/test_ftp.py
+++ b/tests/checker/test_ftp.py
@@ -1,5 +1,5 @@
 # -*- coding: iso-8859-1 -*-
-# Copyright (C) 2004-2010 Bastian Kleineidam
+# Copyright (C) 2004-2012 Bastian Kleineidam
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -36,6 +36,16 @@ class TestFtp (FtpServerTest):
               u"real url %s" % url,
               u"valid",
             ]
+            # ftp use/password
+            user = "anonymous"
+            passwd = "Ftp"
+            url = u"ftp://%s:%s@%s:%d/" % (user, passwd, self.host, self.port)
+            resultlines = [
+              u"url %s" % url,
+              u"cache key %s" % url,
+              u"real url %s" % url,
+              u"valid",
+            ]
             self.direct(url, resultlines)
             # ftp one slash
             url = u"ftp:/%s:%d/" % (self.host, self.port)
diff --git a/tests/test_url.py b/tests/test_url.py
index a9659673..dddfb250 100644
--- a/tests/test_url.py
+++ b/tests/test_url.py
@@ -372,13 +372,13 @@ class TestUrl (unittest.TestCase):
 
     def test_norm_with_auth (self):
         # Test norming of URLs with authentication tokens.
-        url = "telnet://user@www.example.org"
+        url = "telnet://User@www.example.org"
         nurl = url
         self.urlnormtest(url, nurl)
-        url = "telnet://user:pass@www.example.org"
+        url = "telnet://User:Pass@www.example.org"
         nurl = url
         self.urlnormtest(url, nurl)
-        url = "http://user:pass@www.example.org/"
+        url = "http://User:Pass@www.example.org/"
         nurl = url
         self.urlnormtest(url, nurl)