March 16th, 2009

Neighbour table overflow

Cyrus in General Linux Stuff
We had an OES 1 box that was unable to communicate on the network, it was acting like it was recieving a DOS attack but traffic analysis did not indicate this. What we found was a situation where the server was on a network with considerable more hosts then the default ARP cache was able to maintain. The default threshold levels were set too low. We doubled the threshold limits using the information below.

 

How to resolve “Neighbour table overflow” problem?

  

 

Gnu/Linux servers (when used extensively as a server) throw the following messages in log file

  kernel: Neighbour table overflow.
  kernel: printk: 100 messages suppressed.
  kernel: Neighbour table overflow.
  kernel: printk: 151 messages suppressed.
  kernel: Neighbour table overflow.

The solution to the problem is to increase the threshold level for the network devices

To check the present threshold level 1

cat /proc/sys/net/ipv4/neigh/default/gc_thresh1

It will give some value as 128 or 256 or 512.

This can be increased to the next level.Like if the value is 128 then

make the thresh1 value as 256 and thresh2 as 512 and thresh3 as 1024.

echo 256 > /proc/sys/net/ipv4/neigh/default/gc_thresh1

echo 512 > /proc/sys/net/ipv4/neigh/default/gc_thresh2

echo 1024 > /proc/sys/net/ipv4/neigh/default/gc_thresh3

This will stop the Error messages that were recieved in the log file

This was reposted from gnulinuxclub.org
http://www.gnulinuxclub.org/index.php?option=com_content&task=view&id=333&Itemid=49

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April 30th, 2008

Mount Novell Share

Cyrus in General Linux Stuff

First make sure ncpfs is installed:      rpm -q ncpfs
If not install it:     yum install ncpfs
mount volume:     ncpmount -S server-name -A server-dns-name -U username -V volume-name /mnt/where-you-want-to-mount-it

 

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January 14th, 2008

Mount a Windows share on Linux

Cyrus in General Linux Stuff

Yea this is basic stuff but it’s one of those things I dont do it enough to remember the formating.. Perhapes when I can figure out how to live life Windows free I’ll use it more often. Then again MAYBE NOT as I will be windows free!

To test and see if your Linux luv macheen sees the shares on the Windows hate macheen:
smbclient -L <windows-box> -U <username>

Make a directoy for the mountpoint, you know in the mnt directory:

mkdir /mnt/<name-of-mount-point>

Note: Maybe make it something simple like /mnt/stupid_active_directory_server that way everyone knows what it is?? You know cause /mnt/my_horse is good and all but doesn’t tell me what kind of horse it is! YOU KNOW?

Mount the share, yes it’s time to actually mount the horse, put your foot in the stirrups:

mount -t smbfs -o username=<username>,password=<password> //<win-box>/<share> /mnt/<name-of-mountpoint>

Note: This syntax saves the password.
-username=<username>,password=<password>

Create a symbolic link to the mounted drive, i really hope you kow what a symbolic link is:

ln -s /mnt/<name-of-mount-point> /<path-of-symlink>

Note: A symbolic link serves pretty much the same purpose as short cut in Windows. For instance if you linked /mnt/my_stupid_active_directory_server to /msads then you could refer to it as such cd /msads instead of cd /mnt/my_stupid_active_directory_server. Get it?

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