Networking
The specified server cannot perform the requested operation
by Greg on Jan.12, 2010, under Networking, Windows 7, Windows Server
I was not able to access a newly joined Windows 7 computer on our domain from our Windows 2000 Server. I just received that error. “Cannot perform the requested operation” Sharing was setup ok, permissions and security set ok, firewall was turned off. I saw an Event ID 2017 on the Windows 7 system, too. Something about “unable to allocate from the system nonpaged pool”.
I found this online. Add the MaxNonpagedMemoryUsage value below in the client’s registry. (Windows 7 system) Make a restore point first so you can undo if any problems arise.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\MaxNonpagedMemoryUsage
DWORD VALUE: 0xFFFFFFFF
Next, restart the “Server” service on the Windows 7 machine. Then go back to Windows 2000 Server and try to connect to \\window7machine and see if it can access it now.
This worked great for me, hopefully it works for you too. However, it may be wise to increase that value in small increments from the default, which I THINK is 0×100000. I just maxed it out and on my client system to test, and it’s working fine. Just thought I’d make note of it. If you have further problems, or this doesn’t fix the issue, remove the value and reboot. This should return it back to the default.
Exchange 2007 Server Powershell tests
by Greg on Jan.04, 2010, under Exchange Server, Networking
Get the test commands available:
get-help test*
Should list out the tests available to you.
Test overall system health:
test-systemhealth
Check Outlook Web services:
test-outlookwebservices –identity:amailblox@organization.com | fl
(note the “fl” at the end, helps reading output, otherwise it will not wrap the lines)
ZFS CIFS and ACL Inheritance
by Greg on Jul.24, 2009, under Networking, OpenSolaris, Security
This is just another one of those things that didn’t make any sense and only partially does now. At least NOW I know there is more at play here than the simple solutions in Samba using create mask and create directory mask. In Linux, that’s how I would get around the issues of Windows directory permissions running on a Linux SMB share.
Now, I am learning to do things the OpenSolaris way. I am loving OpenSolaris and ZFS! However, coming from a Linux and Windows “way of life”, there are some differences that just aren’t clear. What kills me is, I try the RTFM thing, and somehow completely miss that one little thing that makes it all work. Off topic, but an example, coming from Linux, I would just type “su” and get root access. In OpenSolaris, that won’t work. Neither will “pfexec su”, nor “sudo su”. Then one day, after dealing with it for a week or so, I stumble upon a post where someone in an unrelated sample script typed “pfexec su – root”. There ya go! Argh!
Anyway, back on the ZFS/CIFS/ACL thing. It was driving me nuts that I couldn’t figure it out. I wanted a folder with this setup:
/pool/sharefs – owner:greg – group:domusers
greg and domusers should have full control and all folders under “sharefs” should inherit that.
So under linux/samba, that’s where I would do like “create mask = 770″ or simlar, and “force create group = domusers”. Something like that, can’t remember exactly. made it simple actually. It always wrote files with the right perms and ownership and other people in that group could read/write just fine.
Problem is, you can’t get very specific about who get’s what, where, and you can’t use more than one group. Well, sure enough, there’s a thing called “ACL” that handles that stuff now. It’s been around for a while now, but I never even heard of it until I started using OpenSolaris. I like how it seems to be more compatible with the way Windows handles ACL’s. What I don’t like is, it’s confusing. I get the NTFS/Share perms in Windows, been doing that a long time now. The CIFS/ZFS ACL thing kind of makes sense, and it will “click” at some point the more I use it.
After spending hours on this, I reached a point where I had to figure it out. Here’s what I did.
On the ZFS file system, create it normally for SMB access. Then I changed some properties for aclinherit and aclmode. Change those to “passthrough”:
zfs set -o aclinherit=passthrough -o aclmode=passthrough pool/sharefs
Then chmod/chown. OH! That’s another thing. You need to use /bin/chmod and /bin/ls! Not just type: chmod … That wont work. In OpenSolaris the default path points to /usr/gnu/bin/chmod, which doesn’t have the “A” or “V” options to set/view ACL’s. That was another thing that DROVE ME CRAZY!!! I read the man pages and manuals and docs online and I didn’t catch anything that said, “Hey, there are different versions of chmod and ls here!” I can’t believe the time wasting here! Back to the point, do this to put your own default perms on:
/bin/chmod 2774 /pool/sharefs (I actually am not positive that is needed, but I think it set group as inheritable) /bin/chmod -R A- /pool/sharefs (that will wipe out the current perms) /bin/chmod -R A=owner@:full_set:fd:allow /pool/sharefs (resets perms with only that acl) /bin/chmod -R A+group@:full_set:fd:allow /pool/sharefs (that appends the group perms, full control) /bin/chmod -R A+everyone@:read_set:fd:allow /pool/sharefs (above appends everyone read access)
In all the above that will preset INHERITABLE permissions for the subdirectories. Notice above there is one with “A=” on it? That will reset the perms and set only that perm. So I guess you may not even need the previous line for “A-” to reset. (I am just learning here ya know!)
It looks as if that makes a little sense now. You can view the current ACL’s like so: ”/bin/ls -V /pool/sharefs”
In my case, I might want to add another user or group:
/bin/chmod -R A+user:stacy:full_set:fd:allow /pool/sharefs /bin/chmod -R A+group:othergroup:full_set:fd:allow /pool/sharefs /bin/chmod -R A+group:yetanothergroup:read_set:fd:allow /pool/sharefs
So with this setup I can now open the share on the server and create a file or folder with inherited permissions. It does, however, save my username as a new owner, so keep that in mind. But if the group stays in there with “domusers” as full read/write access, I am happy.
Well, now I get it just a little and it makes more sense compared to Windows ACL’s. I didn’t go over any share specifics and authentication issues, this was just ACL’s! I still have to RTFM my way around that for a while. Next project, join OpenSolaris to a Windows domain. (Which, BTW, does not work in NT Domain style connections, you have to use Active Directory.)
Join Windows 7 to Samba PDC on Ubuntu Jaunty
by Greg on May.31, 2009, under Linux, Networking, Windows 7
I found some info on Google searches to get Windows 7 to join a Samba domain controller. I have Ubuntu 9.04 Jaunty which runs Samba 3.3.2, which I guess does not work. You need 3.3.4. Windows 7 needs a registry change:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\LanmanWorkstation\Parameters]
“DomainCompatibilityMode”=dword:00000001
“DNSNameResolutionRequired”=dword:00000000
The above need to be added to allow the join to work. Then find the key below and set those values to 0.
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Netlogon\Parameters]
“RequireSignOnSeal”=dword:00000000
“RequireStrongKey”=dword:00000000
The Netlogon values need to be updated, or Windows 7 will not allow domain logons. You’ll get an error about credentials and no domain controller, or something like it. Adding the second two will allow the logon.
Adding the registry keys above, plus upgrading Samba, did the trick. I was able to join Windows 7 to Samba 3.3.4, but I did get a weird error about the DNS suffix being wrong. I just said OK and left it. I tried to change it several times after, too, but always get the same error. System working fine so far though!
As for upgrading Samba, you’ll have to Google that one. But here’s what I did, in a nutshell. (This is NOT a HOWTO, just a record of my experience, so if you follow this, it might break your system. Just be warned.) I had a working domain controller, so I had a SAM database already with SID’s and passwords. I didn’t want to lose those. After backing up my server and Samba configs (including all the tdb files) I removed Samba 3.3.2 package from Ubuntu. Then I downloaded the Samba source tar.gz for version 3.3.4, unpacked and “./configure” and then compiled. (make && make install)
At this point I found all my tdb files and copied them into the default Samba installation, which was different than the Ubuntu package. I think the original tdb files from Ubuntu are in /var/lib/samba. I copied all that to /usr/local/samba/var/lock. (the default when compiling from source) I also setup a link from the original smb.conf in /etc/samba to /usr/local/samba/lib/smb.conf.
Now I’ve got my Windows 7 system logged in and joined to my Samba domain!
Ubuntu rndc.key dynamic DNS updates failing
by Greg on May.12, 2009, under Internet, Linux, Networking
Just wanted to add a quick note about this as I couldn’t find a reason why dynamic DNS on my Ubuntu 9.04 system were failing. I had all the right perms, ownership, etc. I even opened up the files to full world writable and still, I got errors that the journal files could not be written to.
Log snippets:
error: journal open failed: unexpected error
jnl: create: permission denied
Learning as I go… there’s a thing in Ubuntu called Apparmor. Never even heard of this. This is what was keeping the files from being written to by the bind daemon. I guess Apparmor has been in this for a while now, but for several yeas now, I have not run into a situation where I had to mess with it.
Here’s what you change. And keep in mind, this is NOT the correct way to handle this on a production or public DNS server. You’ll need to read up more on the correct config for this one. But on my tiny LAN or at home, here’s what I did. In the /etc/apparmor.d directory, edit the usr.sbin.named file. Find the line:
/etc/bind/** r,
Change it to:
/etc/bind/** rw,
Then restart the apparmord daemon. If your DDNS config in Bind and DHCP are correct, you should start seeing successful updates now.
Here’s a coulple links that were helpful on the DDNS setup:
http://brunogirin.blogspot.com/2007/11/dhcp-and-dynamic-dns-on-ubuntu-server.html
http://ubuntuforums.org/showthread.php?t=274665
http://www.ops.ietf.org/dns/dynupd/secure-ddns-howto.html
Also, I wanted to make a note to myself. Creating a new key for DDNS:
dnssec-keygen -a HMAC-MD5 -b 128 -n HOST dhcp-update-key
That creates keyfiles in which you’ll get your key string, this is added in your dhcpd.conf and named.conf.* files as “secret”. RTFM dnssec-keygen. and read up on the links above. :)
Help with Nettiverse naming, FaceBook.
by Greg on Apr.09, 2009, under Geek, Networking
Well I just have too much fun with things like this. I don’t know where it came from, but the Blogosphere was a great name people use. I suddenly thought of Nettiverse because I was trying to connect my blog with Facebook and Twitter. I thought they were pieces of the virtual universe we take part in, the Nettiverse. Now, many people out there are moving away from the Blogosphere and into the Twitterverse. Or maybe it should be called the Twittersphere. Personally, I like Twitterverse.
What’s bugging me is this, Facebook’s name. I haven’t seen or thought up a cool name for it as it exists in the Nettiverse. Anyone out there with a cool idea?
I thought of BookHole! Hahaha! I like it, makes me laugh because that’s exactly what it is, a Black Hole in the Nettiverse. Once you get in, you can’t get out! It sucks you in and wastes away time! But there must be something more fun to call it? Tweet me if you have any ideas. http://twitter.com/gregthegeek
By the way, as people more and more move away from blogs and on to Twitter, I’ve seen a post or two from people suggesting that blogs are a thing of the past. Well, I disagree. I feel they are useful tool. I use my blog mostly as a tech log. Things I like to remember, things I once fixed. The world out there could care less about it, but that’s not the point. It’s for me. I refer back to it, and it’s easy to get online while I am at a client and can’t remember how I solved a problem. Also, the little tidbits I post are found by Google searchers. So, if I find a solution and it helps just one person out there. Right on! Tweets are too short for that. So I like my blog, and I’ll keep using it alongside my Tweets and BookHole. (there’s got to be a better name than that! ??? )
Configure Windows Server 2003 and 2008 w32tm commands on domain controller
by Greg on Apr.07, 2009, under Networking, Windows Server
This drove me nuts! Why Microsoft had to take something totally simple in Windows 2000 and make it a complicated thing is NOT beyond me! This is MS we’re talking about! Of course it’s not easy with newer versions.
Took me a little bit, but here’s the commands I used on our primary domain controller, and it’s working great. that first w32tm command is all one line.
w32tm /config /manualpeerlist:”0.pool.ntp.org 1.pool.ntp.org 2.pool.ntp.org pool.ntp.org”,0×8 /syncfromflags:MANUAL /reliable:yes
w32tm /config /update
net stop w32time
net start w32time
w32tm /resync /rediscover
That should do it. However, always make sure you firewall is open to port 123 outbound! I initially was receiving this error after running a “w32tm /resync” :
The computer did not resync because no time data was available.
In my case, that was caused by my firewall blocking port 123 for NTP traffic. Go figure, we’ve been running this particular network for probably 2 years with that firewall blocking port 123, and only now did someone come and ask “why is our computer time off by 6 or 7 minutes?” This is when you say, “Welcome to the world, can I help you?” (Good old Beavis) Well, at least we got our server configured better as a “reliable” time source with the right ntp.org pools.
Exchange 2007 needs command line to set FQDN of external host name on Send Connector
by Greg on Aug.22, 2008, under Internet, Networking, Windows Server
In Exchange 2007, you have a nice little GUI to set your FQDN on your Send Connector. (Mine is called Outbound, as shown below.)
You can see my FQDN, set under the Hub Transport/Send Connectors of the Exchange Management Console.
However, if you send mail out to an external address, you’ll notice in the headers that your internal server name is still listed! What!? What’s the point of the GUI?
You have top open Exchange Management Shell, and type in a command to solve this. It’s easy.
As shown above, you just type in the command:
set-sendconnector “Outbound” –fqdn mail.1stbyte.com
Replace “outbound” with the name of your send connector, and of course, change to your own FQDN, not mine.
It will come back in error, or success. If success, you can check your headers on and external account right away.
Have fun!
DFS links to shares on Windows XP SP2 do not work on local system
by Greg on Apr.18, 2008, under Networking, PC Repair, Windows Server, Windows XP
Well for the larger businesses out there, this may not be a useful tip. But for those of us that support small networks, like less than 50 or even 10 systems, utilizing shares on workstations is sometimes needed. For example, I have servers in most all of my networks, and their hard drives are fairly large, but I don’t want to save all my downloads and application CD’s on the server. With newer workstations loaded with larger drives than servers sometimes, I’d rather make use of that space there. Not with the main, business critical data, but only things that are not needed for backups or maybe read only archives. These 500+ GB drives give us a ton of space, and when you only have less than 10 people accessing this data periodically, this makes perfect sense. Constant read/write access with lots of users would require the server, rarely accessed stuff goes on a workstation.
Here’s the problem I ran into though. I like to use DFS and create a single shared, mapped drive for all the users. In there I might have a couple shares pointing to workstations. On XP SP2, this works fine, EXCEPT if you are accessing the DFS link from the system where the share resides. You will get an Access Denied error, even with all the correct permissions.
Here’s a registry fix that will overcome the issue.
(Remember, use the registry at your own risk. Back it up if you must. Heck, backup your whole system!)
Open this key on the XP system:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Mup\Parameters
Add a DWORD value:
EnableDfsLoopbackTargets
Change its value to 1.
Reboot the system.
Your share should now be working from DFS mapped drive from the local system. (the local system where the share is located.)
Find an email address that already exists in Active Directory
by Greg on Apr.14, 2008, under Networking, Windows Server
So you went to add a new address to a user account in Active Directory, and you got an error that this address already exists? Sucks huh? Especially when you don’t know where it could be? Here’s one way to track it down.
On your domain root in AD Users and Computers, right click, select Find. Select Custom Search, click the Advanced tab, and enter an LDAP query like so:
proxyaddresses=smtp:emailaddress@youwanttofind.com
(I am assuming you are not a complete NEWB and you know you should replace that email with the one you want.)
Then click the Find Now button. You should see a in the results below any object that may have this address on it.
New account does not appear in Global Address List but does in All Users
by Greg on Mar.27, 2008, under Internet, Networking, Windows Server
I’ve run into this a few times, thought I’d record the solution for once so I remember it.
After adding a new user account, the user does not show up in Outlook’s Global Address List, but does show in All Users. (If you click “To” in a new message, for example, and in the Select Names windows under “Show names from the:” drop down, you select All Users.) Even if I go into Active Directory Sites and Services and manually force replication it does not work. (under the NTDS Settings for each server) Normally, I would even go into Recipient Update Services and manually update, but this does not work either.
I found out that if you have Outlook in Cached Exchange Mode, the Global Address List does not update for up to 24 hours. I don’t know the details on that, but I can force it to update. This is on a per-machine basis, so doing this across the whole network won’t work. (Although, there may be a way to do this, I just don’t know how.)
Go into Outlook, go to Tools, Send/Receive, then click Download Address Book. Make sure you have Global Address List under the Choose Address Book drop down, and click OK. Problem solved.
By the way, I am using Exchange 2003 and Outlook 2003.
Folder redirection user permissions block access to Administrators
by Greg on Mar.19, 2008, under Networking, Security, Windows Server
When using Folder Redirection on a Windows 2003 server, the default policy is allow only ownership and permissions to the user. No admin account would have access to this folder. For example, you create a Group Policy to redirect user’s My Documents folders to a home directory on the server. Once a user logs on and this policy is applied, the folder is created with ownership of the user only, and file permissions granted for that user only, too.
This has presented a big problem for me, having come from Windows 2000, where this was not the case. As you might guess, when only the user has permissions specified, no administrator can get access to this folder for backup purposes. Our backups always failed.
Well then, on Windows 2003 Server, two default policies are in place making the user’s folders more secure. Nice, but I don’t care. I want backup rights by default. Go into the Group Policy where you would like to define the new policy. I made a new Organizational Unit and put all my computers in there, so I could define the policy at a lower level, instead of at the domain level. Once into and editing you policy, drill down to here:
Computer Configuration –
Administrative Templates -
System –
User Profiles –
In here look for these two policies and enable them:
“Do not check for user ownership of Roaming Profile Folders”
“Add the Administrators security group to roaming user profiles”
Now this will allow Windows 2003 to behave more like Windows 2000 on the redirected folders. Unfortunately, there is one issue. It does not change permissions on previously created folders, only on newly created folders. That’s a pain, but not that big a deal, because I can probably script some folder moves and recreate them.
Also, even though this says “Roaming” in the policy items, they apply to local and roaming accounts. So even if your users are normal, non-roaming profiles, you still need to set. In my case, we did not have any roaming profiles and only used folder redirection OR simply had home folders mapped from the server. Doing either of those had the same permissions problem and the policies mentioned solved the issue. (except for previously created folders, it only changes on newly created folders after the policy change.)
Resetting NTFS permissions are not taking effect on child objects
by Greg on Mar.19, 2008, under Networking, Security, Windows Server
Recently I went to reset a user’s home directory permissions on the server to allow them full control over each file/folder in their home directory. I setup all the normal accounts and of course the actual user account, with Full Control. I then went into Advanced and selected “Replace permission entries on all child objects” and hit apply.
This seemed to work fine, except the user complained that they could not access the documents in certain subfolders. When I checked those subfolders, the permissions were correct, except for her account had no permissions specified. Essentially this means, no perms, no access. So I tried again, same result.
The solution was simple, though, I can’t figure out why this was configured this way. At the root folder you wish to start inheritance, go into advanced under security on that folder. Go into Advanced again, and under Permissions, highlight the user in question, and click Edit. Under the detailed Permission Entry window, at the very bottom is a checkbox for:
“Apply these permissions to objects and/or containers within this container only.”
Uncheck that! And apply the permissions once more. All child objects should now have all the correct permissions! Yay!
I don’t understand why this is set this way. Is there a Group Policy in place I don’t know about? Did a previous IT guy change that? At least I have a solution. J
IE7 fails to automatically authenticate with enable integrated windows authentication checked
by Greg on Mar.15, 2008, under Internet, Networking, Web Design
In Internet Explorer 7, Tools, Internet Options, Advanced tab. The checkbox for “enable integrated windows authentication” is very confusing. You would think this means “just log me in with my windows credentials”, but no, there’s more to it than that. And what I found was, it simply enables “Negotiate”. It set’s this registry key to 1:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\EnableNegotiate
After some research, this actually means that IE will negotiate between NTLM or Kerberos authentication. In some situations, Kerberos will fail. I don’t understand well enough to explain this one. But that’s ok, because the point of all this is… I want IE to authenticate automatically on my Intranet! Anyway, if you uncheck this setting in IE, it will set Negotiate to disabled. (0) If Negotiate is disabled, IE will use NTLM by default. BAM! I can login automatically.
Wouldn’t it be much more helpful if Microsoft had labeled that for what it was? Like: Negotiate Kerberos or NTLM Authentication.
Word of caution… some Intranet apps might depend on Kerberos, so this might cause more problems down the road of you disable this on all your client systems.
Another note… IE6, as I understand it, does not behave this way. It has a similar setting to enable windows authentication and I believe it uses NTLM by default. I HAVE NOT TESTED THIS, and I don’t know for sure if this is true, but according to my Googling, this is the case.
I found this site with info regarding EnableNegotiate:
http://ie7triage.spaces.live.com/blog/cns!3B6634EF5458F389!422.entry
Here’s another blog you might find useful:
http://blog.super-networking.net/systems/internet-explorer-enable-integrated-windows-authentication/
Is a hardware firewall really a software firewall anyway?
by Greg on Mar.05, 2008, under Internet, Linux, Networking, Security
I love how people always say that a software firewall like IPCop is a “lesser” product than a hardware system. I ran into one site speaking of Netsentron as a hardware solution. I’d also include Endian Firewall and Untangle when we talk about a “linux based hardware firewall”. Well here’s my thought. These systems offer a hardware solution, but aren’t these products really the same thing as the downloaded software version they provide? And if so, these products are really only a “hardware/software bundle”, right? (I think they actually advertise them this way anyway, but my gripe is with all those techs out there under the notion that these are real hardware based products.)
I can’t comment on any Cisco or Sonicwall, hardware firewalls, because I have not used any of them. But are these also just software running on hardware? And the main thing I’ve heard from security people about the lesser quality software products is that they are not good at defending against DOS attacks. Is this really true? Even if so, in the last 10 years I’ve ran some sort of Linux based firewall, whether home-brewed or special firewall distribution, I’ve not once had a break in. I’ve not once had a DOD attack. (THIS IS NOT AN INVITATION!)
Now, I have had a DOD attack directly on and Exchange or IIS server that was port forwarded directly to the Internet. Not pretty! Which is a big reason why I don’t run these systems directly anymore. But this is off topic. (maybe another blog coming!)
I’ll do some of my own research, but maybe if someone out there can shed some light on the deficiencies of a Linux firewall, in particular IPCop or Smoothwall. For my use, IPCop with a few addons, make for a fantastic filtering firewall, provided we pick good hardware to run it, and configure it properly. Is Sonicwall truly better at providing security?
Ah, just thinking out loud again. I am sure someone out there will give me hell for saying things like this. I am not a security expert, not even close. But, sometimes I just wonder about things… J