Troubleshooting Unix / Linux Servers

Troubleshooting tips about Linux, *BSD, UNIX, Apple OS X, programming and MS-Windows servers and desktop systems ( rss feed ).

I setup a CentOS Linux based Linux server running as a gateway and firewall server. However, I’m getting the following messages in the /var/log/messages log file:

Dec 20 00:41:01 fw01 kernel: Neighbour table overflow.
Dec 20 00:41:01 fw01 last message repeated 20 times

OR


Dec 20 00:41:01 fw03 kernel: [ 8987.821184] Neighbour table overflow.
Dec 20 00:41:01 fw03 kernel: [ 8987.860465] printk: 100 messages suppressed.

Why does kernel throw “Neighbour table overflow” messages in syslog? How do I fix this problem under Debian / CentOS / RHEL / Fedora / Ubuntu Linux?

{ 2 comments }

I‘m trying to install the latest version of Lighttpd v1.4.29 web server under RHEL 6.1 AMD64 and getting the following error:

network.c: In function ‘network_init’:
network.c:483: error: ‘EC_KEY’ undeclared (first use in this function)
network.c:483: error: (Each undeclared identifier is reported only once
network.c:483: error: for each function it appears in.)
network.c:483: error: ‘ecdh’ undeclared (first use in this function)
network.c:484: warning: unused variable ‘nid’
make[3]: *** [network.o] Error 1
make[3]: Leaving directory `/opt/new/lighttpd-1.4.29/src’
make[2]: *** [all] Error 2
make[2]: Leaving directory `/opt/new/lighttpd-1.4.29/src’
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/opt/new/lighttpd-1.4.29′
make: *** [all] Error 2

How do I fix this problem under CentOS 5.x, or RHEL, or Red Hat Enterprise Linux 6.x, or Fedora Linux?

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I‘m using RHEL 6 / CentOS 6.x and install the memcached server. However, whey I try to start the server using service memcached start command, I get the following error:

Starting memcached: failed to set rlimit for open files. Try running as root or requesting smaller maxconns value. [FAILED]

How do I fix this problem?

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I‘ve recently regenrated and uploaded a new public ssh-key using the ssh-copy-id command. Now I’m getting the following error:

ssh root@server3
Agent admitted failure to sign using the key.
root@server3’s password:

How do I fix this problem?

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I recently installed NFS server v4 on my HP Linux server. However, I’m not able to mount it from Linux nfs4 client using the following command:

mount.nfs4 server2:/data /data

I’m getting the following error:

mount.nfs4: mounting server2:/data failed, reason given by server:
No such file or directory

How do I fix this problem?

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I‘m using an external display with a MacBook Pro. I do not want to use the external monitor as a mirrored display. I need to move the dock and the menu bar to external monitor. How do I setup the external monitor as main display?

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I want to use my local machine as the X server over ssh. But when I try to run ssh -X -v user@server1.example.com to the remote machine, I get the following error:

debug1: Remote: No xauth program; cannot forward with spoofing

How do I fix this problem and use X over ssh?

{ 1 comment }