Category: LAN Networking

Mount NFS Shares in Linux
article #1045, updated 29 days ago

So you have an NFS server share known to be working, and you want to mount its share(s) on your Linux client machine. Here’s a summary. All commands are in “sudo -s” or root login.

  1. Let’s postulate that the server share is visible on server, and its name is “/srv/nfs”.
  2. We need a place to mount the share on this machine. So:
    mkdir /nfs
  3. Next we try it manually:
    mount -t nfs /nfs
  1. We now make sure that permissions allow users of the mounting machine read/write access to the share. By far the simplest way this author has found to do this, is to have the shared folder and all contents chmoded g+rwXs, chgrped to a sharing-designated group, on the server side. On the client side what’s to do, is to make sure that sharing-designated group exists with the same GID. So let’s say the group we’re designating for sharing setup is called “sharegroup”. Before we set this up, a ls -l from root on the client machine may look something like this:
drwxrwsr-x 11 1000 1001 4096 May 14 04:06 folder1
drwsrwsr-x 25 1000 1001 4096 Apr 19 07:49 folder2
drwsrwsr-x 21 1000 1001 4096 Apr 18 23:53 folder3

If you compare with ls -l of a local folder, you’ll see that the third and fourth fields from the left should be owning username, and owning groupname. The groupname as viewed from the server will be “sharegroup” if things are set according to this method. You will need to add a group on the client side, with the same name and GID, i.e., if ‘1001’ were really the GID as above:

groupadd -g 1001 sharegroup

And then add yourself to ‘sharegroup’ on the local machine:

usermod -a -G sharegroup username

A logoff and logon is then best, to make sure all of the security settings are activated.

  1. Then we set up automount at boot. We do this by adding the following line to the end of /etc/fstab:   /nfs   nfs   rsize=8192,wsize=8192,timeo=14,_netdev,intr	0 0

The final option “intr” is instead of “hard” or “soft”. It makes NFS transactions explicitly interruptible, which helps prevent corruption if the server goes down.

Categories:   LAN Networking   Linux OS-level Issues


Time synchronization (NTP, SNTP) setup
article #37, updated 187 days ago

In Windows Server 2012 R1/2, 2008 R1/2, 7, Vista, and 2003 SP2 and later, it’s good to run the following two commands in an administrative command prompt (an ordinary command prompt for 2003):

w32tm /config /,,, /syncfromflags:MANUAL /reliable:YES /update
w32tm /resync

In Server 2003 SP1 and before, and XP, we use this, because /reliable doesn’t exist:

w32tm /config /,,, /syncfromflags:MANUAL /update
w32tm /resync

Sometimes w32tm doesn’t exist as a service, and has to be registered:

w32tm /register

Under Windows 2000, we need to go a bit more archaic:

net time /
net time /querysntp

If you are using Windows DHCP services, the above is best for the server, but for all of the workstations under its control, place the server’s IP in the Time Server option. This is probably best for a domain. When you have standalone or mobile-capable machines, best to just use the w32tm configuration above.

Categories:   Internet Networking   LAN Networking


Set Static IP, DNS, and WINS using the 'netsh' command
article #962, updated 365 days ago

If you’re working remotely, you don’t want your connection to go down, so we need to do it all in one command. So:

netsh interface ip set address "Local Area Connection" static <PC-IP> <Subnet-Mask> <Default-Gateway> & netsh interface ip set dns name="Local Area Connection" static <Primary-DNS> primary & netsh interface ip add dns "Local Area Connection" <Secondary-DNS> index=2

Be sure not to include the <> characters when replacing!

Categories:   LAN Networking   


Internet connection speed tests
article #182, updated 497 days ago

Here’s a great new one, HTML5 only, no Flash or Java:

Here’s a commonly used one which requires Flash:

And another which uses java:

Categories:   Internet Networking   LAN Networking


IP4 subnet calculators
article #79, updated 634 days ago

For CIDR to IP range (IP range extraction):

For IP range to CIDR:

For lots and lots more:

Categories:   Internet Networking   LAN Networking


Windows 7 libraries, network drive letter mapping, and My Documents redirection
article #112, updated 1693 days ago

A few notes:

  1. In the original shipping version of Windows 7, NET USE commands in login scripts and command shells did not work.  After about two months, however, if all updates were installed, they began working.  This method still works well, and is not disrecommended.
  2. Windows 7 libraries are the way to do the equivalent of “My Documents” redirection.  They can be set manually.  Just right-click on a library and go to Properties, and you can direct it wherever you want.
  3. But if the server does not have Windows Search 4 or higher, you will not be able to do your redirections as in #4.  For this, you have two options. First, you can set Offline Files for the folder in question. Or second, you can use a wonderful third-party utility at the following location:

Categories:   LAN Networking   


Hidden IPv6 on XP and Server 2003
article #431, updated 1877 days ago

Sometimes IPv6 is installed on XP in a hidden form — sometimes IPv6 may be installed, but not visible in any Windows GUI. To find out, go to command prompt and enter:

netsh show helper

If IPv6 is installed, in that list will be “ipv6”. To uninstall on XP, run this:

ipv6 uninstall

The ipv6 command does not exist on Server 2003. The following does:

netsh delete ipv6mon.dll

Hidden IPv6 has been shown to cause problems in some Oracle environments.

Categories:   LAN Networking   Internet Networking


Set NetBIOS over TCP/IP using command line
article #426, updated 1888 days ago

First get a list of interfaces:

wmic nicconfig get caption,index,TcpipNetbiosOptions

Make note of the number of the interface you want to change. Once you have it (for example, number 0000009), do this to enable:

wmic nicconfig where index=9 call SetTcpipNetbios 1

List of options:

0 – Use NetBIOS setting from the DHCP server
1 – Enable NetBIOS over TCP/IP
2 – Disable NetBIOS over TCP/IP

Categories:   LAN Networking   


Windows 7 mapped drive disconnects
article #402, updated 1945 days ago

If you find that mapped drives disconnect without rhyme or reason, go here and do what Liz found for all of us:

Categories:   Windows OS-Level Issues   LAN Networking


Simple File Sharing in Windows 7
article #364, updated 2045 days ago

Go to the Start ball, enter “Folder Options” in the search box. Under “View”, far down in the checkbox options, you’ll see “Sharing Wizard”. Turn that off, to turn off simple file sharing in 7.

Categories:   Windows OS-Level Issues   LAN Networking