Kerberos is a computer network authentication protocol, which allows nodes communicating over a non-secure network to prove their identity to one another in a secure manner. Its designers aimed primarily at a client–server model, and it provides mutual authentication — both the user and the server ...

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5answers
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Why use Kerberos instead of NTLM in IIS?

This is something that I've never really been able to answer as well as I like: What is the real advantage of using Kerberos authentication in IIS instead of NTLM? I've seen a lot of people really ...
19
votes
1answer
4k views

Authenticating OpenBSD against Active Directory

Edit: Reformatted this as Q&A. If anyone can change this from Community Wiki to a typical question, that's probably more appropriate as well. How can I authenticate OpenBSD against Active ...
14
votes
3answers
33k views

Getting Squid to authenticate with kerberos and Windows 2008/2003/7/XP

This is something I setup recently and was quite a big pain. My environment was getting squid to authenticate a Windows 7 client against a Windows 2008 Server invisibly. NTLM is not really an ...
11
votes
5answers
2k views

Which kerberos flavor?

So I'm setting up a small network with all the standard stuff (files, email, etc.) and I've decided to go with a Kerberos+LDAP solution. Any ideas or recommendations on Heimdal vs. MIT? I've used MIT ...
11
votes
2answers
2k views

The Story of secure user-authentication in squid

once upon a time, there was a beautiful warm virtual-jungle in south america, and a squid server lived there. here is an perceptual image of the network: <the Internet> ...
10
votes
2answers
893 views

How can I log into a Domain controller that doesn't trust itself

I have a windows 2008 R2 standalone Domain Controller that I restored from backup. The original DC is offline. When I log in with valid user credentials I get the error: "The security database ...
10
votes
2answers
3k views

Can someone please explain Windows Service Principle Names (SPNs) without oversimplifying?

I have wrestled with service principle names a few times now and the Microsoft explanation is just not sufficient. I am configuring an IIS application to work on our domain and it looks like some of ...
10
votes
3answers
2k views

How to deny access to disabled AD accounts via kerberos in pam_krb5?

I have a working AD/Linux/LDAP/KRB5 directory and authentication setup, with one small problem. When an account is disabled, SSH publickey authentication still allows user login. It's clear that ...
9
votes
2answers
572 views

Demoted domain controller still authenticating users

Why is a demoted domain controller still authenticating users? Whenever users log onto workstations with domain accounts, this demoted DC authenticates them. Its security log shows their logons, ...
9
votes
1answer
351 views

Kerberos authentication, service host and access to KDC

I have a web application (hostname: service.domain.com) and I wish to use Kerberos authentication to identify users that are logged into a Windows domain. Microsoft AD (Windows Server 2008 R2) is ...
9
votes
2answers
513 views

Any options out there for kerberized ssh client on windows?

Are there any good (reliable / free) ssh clients that work easily with Active Directory authenticated accounts in a Windows environment? Ideally that wouldn't need the Kerberos for Windows package? ...
8
votes
4answers
5k views

How do I get /dev/random to work on an Ubuntu virtual machine?

Apparently, /dev/random is based on hardware interrupts or similar unpredictable aspects of physical hardware. Since virtual machines don't have physical hardware, running cat /dev/random within a ...
8
votes
1answer
1k views

IPA vs just LDAP for Linux boxes - looking for a comparison

There are few (~30) Linux (RHEL) boxes and I'm looking for centralized and easy managed solution, mostly for control user accounts. I'm familiar with LDAP, and I deployed a pilot of IPA ver2 from Red ...
8
votes
4answers
4k views

Linux Central Authentication/Authorization Methods

I have a small but growing network of Linux servers. Ideally I'd like a central place to control User Access, change passwords, etc... I've read a lot about LDAP servers, but I'm still confused about ...
8
votes
1answer
2k views

How to tell mod_auth_kerb to do its job despite no “require valid-user”

I implemented a SSO authentication using mod_auth_kerb on Apache. My config looks like this: <Location /login/ > AuthType Kerberos AuthName "Kerberos Login" KrbMethodNegotiate on ...
8
votes
2answers
2k views

How does Kerberos work with SSH?

Suppose I have four computers, Laptop, Server1, Server2, Kerberos server: I log in using PuTTY or SSH from L to S1, giving my username / password From S1 I then SSH to S2. No password is needed as ...
8
votes
1answer
1k views

NFS (with Kerberos) mount failing due to “Server not found in Kerberos database” error

When running: sudo mount -t nfs4 -o sec=krb5 sol.domain.com:/ /mnt I get this error on the client: mount.nfs4: access denied by server while mounting sol.domain.com:/ And on the server syslogs I ...
7
votes
6answers
28k views

How do you find out if Active Directory is using Kerberos or NTLM?

Is there a command line program you can use?
7
votes
1answer
2k views

Best practice for authenticating DMZ against AD in LAN

We have few customer facing servers in DMZ that also have user accounts , all accounts are in shadow password file. I am trying to consolidate user logons and thinking about letting LAN users to ...
7
votes
3answers
4k views

Virus that tries to brute force attack Active Directory users (in alphabetical order)?

Users started complaining about slow network speed so I fired up Wireshark. Did some checking and found many PCs sending packets similar to the following: (screenshot) http://imgur.com/45VlI.png I ...
7
votes
1answer
98 views

Kerberos: Separating AS and TGS

In Kerberos, the Authentication Server (AS) and the Ticket Granting Server (TGS) are generally implemented on the same server. This machine is called the Key Distribution Center (KDC). Surely, it ...
7
votes
3answers
451 views

Ubuntu 12.04, Windows 2012 Active Directory Integration, Kerberos won't resolve service principals

after having checked the whole internet literally, I hope that I might get help here. I am trying to accomplish integration of ubuntu 12.04 servers into a Windows 2012 active directory with nfs and ...
7
votes
3answers
432 views

Permissions are not taking effect with Kerberised NFSv4 on FreeBSD

I'm currently trying to set up an NFSv4 server on FreeBSD. I have extensive experience with doing this on other Unices (Solaris and Linux), but I'm fairly new to FreeBSD. My goal is to achieve the ...
6
votes
3answers
6k views

Apache mod_auth_kerb and LDAP user groups

I've been considering deploying mod_auth_kerb on our internal web servers to enable SSO. The one obvious problem I can see is that it's an all-or-nothing approach, either all your domain users can ...
6
votes
2answers
684 views

NetApp erroring with: STATUS_NOLOGON_WORKSTATION_TRUST_ACCOUNT

Since a sitewide upgrade to Windows 7 on desktop, I've started having a problem with virus checking. Specifically - when doing a rename operation on a (filer hosted) CIFS share. The virus checker ...
6
votes
1answer
5k views

Seamless SSO with Kerberos, IE, Firefox, LDAP Active Directory

Alias /students /var/www/students <Location /students> KrbServiceName HTTP KrbMethodNegotiate On KrbMethodK5Passwd On KrbSaveCredentials off KrbAuthRealms DOMAIN.LOCAL Krb5KeyTab ...
6
votes
1answer
123 views

Time taken for authentication to work again after changing system time

One of our domain controllers clock drifted way out of sync with the rest of the network (thanks to me forgetting to turn off VMWare's time synchronisation), which caused a whole bunch of servers to ...
6
votes
0answers
2k views

Kerberos NFS4 permission denied [closed]

** Edit: ** I am not using Sabayon Linux anymore and this problem didn't occur on other distributions. I suggest to close this question. Update: I realized that because of bad hosts file, both ...
6
votes
0answers
402 views

What breaks in a Windows domain if a member has a high time skew? [closed]

It's taken for granted by most IT people that in a Windows domain, if a member server's clock is off by more than 5 minutes (or however many minutes you've configured it for) from that of its domain ...
5
votes
2answers
2k views

Is there a way to get Kerberos credentials to delegate twice? Why not?

All my nerdly life, I've dealt with this limitation of Windows Domains Login - console Integrated auth to something (usually web app) My credentials can't move to another server (e.g. database or ...
5
votes
4answers
255 views

Locking a user's account locally when kerberos is enabled

I'm trying to set up Chef-managed accounts for a group of machines with the following characteristics: If there is no local account, login is blocked. If there is a local account with SSH keys, use ...
5
votes
2answers
401 views

Risks of Kerberos Delegation

I've been spending hours upon hours trying to learn and understand Windows Authentication, Kerberos, SPNs, and Constrained Delegation in IIS 7.5. One thing I just don't get is why it is "risky" to ...
5
votes
1answer
2k views

Permissions to create an spn

According to some of the documentation I've read the service account for SQL server will create an SPN when the database engine starts up, allowing for kerberos authentication. I haven't been able to ...
5
votes
2answers
1k views

What is SASL/GSSAPI?

Numerous times i have met the expression SASL/GSSAPI. I have searched Google many times, but i simply do no understand what it is and how it relate to Kerberos. Anybody that have a simple explanation ...
5
votes
4answers
7k views

How to re-join an AD2003 domain with Samba after deleting the machine account?

During some troubleshooting I deleted the machine account for a Linux server running samba from our AD 2003 domain. We are using Kerberos for authentication, and after I deleted the machine account I ...
5
votes
3answers
1k views

SSH Kerberos authentication fails with “Wrong principal in request/Got no client credentials” on debian squeeze

I have a debian squeeze host where I can't log in with kerberos without a password prompt. An identically configured ubuntu 12.04 host works fine and can log in without getting a password prompt. ...
5
votes
2answers
6k views

ActiveDirectory Kerberos keytab unusable from Linux

I am configuring Kerberos authentication for Alfresco CIFS protocol fully implemented in Java (JLAN project). That is not the first time, I used to set it up right in a single shot. In the same ...
5
votes
3answers
15k views

mount.nfs: access denied by server while mounting (Kerberos authentication)

There's plenty of references to this error on Goggle, and even a question here with the same title, but it seems that "access denied by server while mounting" is a catch-all error. I've tried ...
4
votes
4answers
11k views

Running a Windows service under a domain user account

If I run a Windows service on some host under a domain user account, and the password for this account changes at some later point, will the service now fail to start, until you update the password? ...
4
votes
3answers
3k views

Can Windows integrate with LDAP?

Given an existing LDAP server used for authentication, can Windows desktops authenticate users against LDAP or perhaps Kerberos?
4
votes
2answers
781 views

Double Hop Window Authentication

I've got a problem getting Windows Authentication (Kerberos) to work when passing credentials from the user, to IIS then from IIS to SQL. I have setup SPN's for SQL, and set the IIS server account up ...
4
votes
1answer
12k views

Create SPN with setspn.exe - Insufficient access rights

On a Windown Server 2008 Domain Controller, I'm attempting to add a Service Principal Name (SPN) to a user account 'Postmaster' in order to enable Kerberos authentication from a Communigate email ...
4
votes
1answer
1k views

How to integrate Active Directory with FreeBSD 10.0 using security/sssd?

What are the required steps to authenticate users from an Active Directory running on Windows Server 2012 R2 in FreeBSD 10.0 using sssd with the AD backend with Kerberos TGT working?
4
votes
3answers
237 views

Multiple Realms and Multiple TGTs under MIT Kerberos for Windows

My local computer uses Windows 7 Pro and belongs to realm LR, managed by AD servers. I login to my computer while attached to that realm's network. I can view the TGT with MIT Kerberos for Windows ...
4
votes
4answers
13k views

How can I check if my IIS site is using NTLM or Kerberos?

How can I check if my IIS site is using NTLM or Kerberos? And how can I change authentication from Kerberos to NTLM? I'm using IIS 7.5 and I couldn't find any answer to this question, can help me a ...
4
votes
3answers
419 views

Linux on Windows AD Domain

Successfully joined my Linux Box to a Windows AD Domain. Wanted to know from other admins if it us possible to specify what groups from windows ad is allowed to login? Otherwise anyone with a AD ...
4
votes
4answers
4k views

Authenticating Windows 7 against MIT Kerberos 5

I've been wracking my brains trying to get Windows 7 authenticating against a MIT Kerberos 5 Realm (which is running on an Arch Linux server). I've done the following on the server (aka dc1): ...
4
votes
1answer
3k views

Relative security of SAML vs Kerberos

Does anyone have any info/links on the relative security of SAML vs Kerberos. I believe I grasp the differences between the two, and what they mean for my particular application, but to decide ...
4
votes
1answer
9k views

Creating keytabs and service principal names

I'm trying to set up a keytab for a Java server to support Kerberos authentication on a Windows network. I'm struggling to get it working even at the level of the command line tools, haven't even got ...
4
votes
1answer
4k views

Track Down Which Process/Program is Causing Kerberos pre-authentication error (Code 0x18)

We have a domain account that is being locked out via 1 of 2 servers. The built-in auditing only tells us that much (locked out from SERVER1, SERVER2). The account gets locked out within 5 minutes, ...