Apply single sign-on for computers not in ActiveDirectory domain

I have one Windows AD server, and one Linux server which runs Apache and Subversion, also have one Windows server runs .net web application which use Windows Authentication.

I already configured out how apply Kerberos or GSSAPI to auth subversion users with AD credentials, and the users use computers which joined domain won't prompt a window ask for user and password when access .net web app and svn.

But these users who are not join domain always prompt a window ask for user and password both of web app and svn twice, I want to share login credential for the two applications, how can I apply?

Thanks.

krb5.conf:

[logging]
 default = FILE:/var/log/krb5libs.log
 kdc = FILE:/var/log/krb5kdc.log
 admin_server = FILE:/var/log/kadmind.log

[libdefaults]
 default_realm = SCRCUTEST.COM
 forwardable = true
 dns_lookup_realm = false
 dns_lookup_kdc = true
 rdns = false

[realms]
 SCRCUTEST.COM = {
  kdc = astest.scrcutest.com
  admin_server = astest.scrcutest.com
 }


[domain_realm]
 .scrcutest.com = SCRCUTEST.COM
  scrcutest.com = SCRCUTEST.COM

resolv.conf:

domain scrcutest.com
nameserver 10.16.0.37

http.conf:

   <Location /svn>
    DAV svn
    SVNParentPath /data/bb_bak/PV/access

    SVNListParentPath On
    SVNAutoVersioning On

    AuthType Kerberos
    AuthName "Input AD account"
    KrbAuthRealms SCRCUTEST.COM 
    KrbServiceName HTTP
    Krb5Keytab /etc/httpd/conf/kerberos.keytab
    KrbMethodNegotiate On
    KrbVerifyKDC Off
    KrbMethodK5Passwd Off
    KrbSaveCredentials on 
    Require valid-user
   </Location>