Linux Networking





The variety of Linux distributions creates myriad issues relating to configuration and operations when computers are networked, not the least of which is the use of various network management applications, some of which are included with specific distributions, while others are standalone applications.

Share tech news, updates, or what's on your mind.

Sign up to Post

Here is all I did:

I installed Ubuntu Server 12.04.4 in a VirtualBox.  Network is bridged.  Then I ran:
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install vsftpd

Then I edited /etc/vsftpd.conf and uncommented local_enable=YES and write_enable=YES.  
Saved the config.
sudo service vsftpd restart
sudo ufw disable  (for good measure)

So then I go into Filezilla on the host machine and try to connect, but this is what I get:

Status:      Connecting to
Status:      Connection established, waiting for welcome message...
Response:      220 (vsFTPd 2.3.5)
Command:      USER jsmith99
Response:      331 Please specify the password.
Command:      PASS *********
Response:      500 OOPS: priv_sock_get_result
Error:      Critical error
Error:      Could not connect to server

Any ideas on what the heck am I doing wrong?  I'm pretty sure this has worked for me very easily in the past, although it's been a while.  And I don't remember if I've done it in Virtualbox before.

Any help is appreciated!  Thanks.

[edited my username out]
Despite specifying no_root_squash, root most definitely is getting squashed. This makes it difficult when i need to access the share as root (e.g. with Clonezilla).

Access denied to tree /bk. /etc/exports is
# /etc/exports: the access control list for filesystems which may be exported
#		to NFS clients.  See exports(5).
# Example for NFSv2 and NFSv3:
# /srv/homes       hostname1(rw,sync) hostname2(ro,sync)
# Example for NFSv4:
# /srv/nfs4        gss/krb5i(rw,sync,fsid=0,crossmnt)
# /srv/nfs4/homes  gss/krb5i(rw,sync)

Open in new window

I have a shared folder in Samba. Everyone access the folder by mapping a drive in Windows and can put their files or folders there for sharing. However when one user create a folder or a file, it does not allow others to edit or can put other files into that folder. How can I set the permission to be autormatically granted for all others whenver one user create a file or a folder ???

We have suffered a couple of serious Syn Flood attacks recently.  We thought we had put the right levels of protection on our server, but we are now seriously considering using a web based service (see list below).

What should we look out for with these services?

What should we expect to pay for the services?

Does anyone have any particular recommendations?

Many thanks
i am in need of step by step guide for configuring SUSE linux enterprise high availability Extension cluster.for two node scenario in vmware v center.
we are trying to connect from external application to fuse. During telnet, we are getting below error.

Escape character is '^]'.
ðActiveMQ       Þ
                        MaxFrameSizeÿÿÿ CacheSize
                                                 CacheEnabledSizePrefixDisabled MaxInactivityDurationInitalDelay'TcpNoDelayEnabledMaxInactivityDurationu0TightEncodingEnabledStackTraceEnabledConnection closed.

I can't access my domain via IP address or website:
Also, the other domain associated with this VPS on godaddy (service is pretty bad I think compared to other VPS providers I've had. Just my input and opinion).

I think it could be related to a WHM update but not sure.

I can access the cPanel via WHM (Home->Account information->List Accounts). Also, FTP works fine. Ping works fine too.

So I'm thinking related to the DNS records but not sure.

This is what I have in my logs:

Apr  4 09:55:49 ip-184-168-116-73 pure-ftpd: (?@ [INFO] __cpanel__service__auth__ftpd__6r_VrEy0gEHWu9LjKzV27w_Xxg9d62wAzi3re9ayywHK3Lvfb3942fAmkKAENRNF is now logged in
Apr  4 09:55:50 ip-184-168-116-73 pure-ftpd: (__cpanel__service__auth__ftpd__6r_VrEy0gEHWu9LjKzV27w_Xxg9d62wAzi3re9ayywHK3Lvfb3942fAmkKAENRNF@ [INFO] Logout.
Apr  4 10:00:49 ip-184-168-116-73 pure-ftpd: (?@ [INFO] New connection from
Apr  4 10:00:50 ip-184-168-116-73 pure-ftpd: (?@ [INFO] __cpanel__service__auth__ftpd__aRUhrLg6d3tUtpi4IDgOu4KqynW7Q_WEAjpHLXcVBfLP70X8Vnx3cugIbkP2l89Z is now logged in
Apr  4 10:00:50 ip-184-168-116-73 pure-ftpd: (__cpanel__service__auth__ftpd__aRUhrLg6d3tUtpi4IDgOu4KqynW7Q_WEAjpHLXcVBfLP70X8Vnx3cugIbkP2l89Z@ [INFO] Logout.
Apr  4 10:03:02 ip-184-168-116-73 named[7207]: network unreachable resolving '': 

Open in new window


I want to delete and remove a domain associated with my VPS via WHM cPanel.

There is an additional option in the Home->Account Functions->Terminate an Account checkbox stating:

Keep DNS Zone (necessary if removing an account because you have already moved it to a different server in the same DNS cluster)

What do they mean by "same DNS cluster"? I guess I don't have to have it checked since I haven't moved it to a different server, correct?

Thank you,
Dear all,

I run a cisco asa 5510 and I want to know how to configure the asa to let some of VPN client users navigate through the remote gateway (with remote public ip). We are using AnyConnect VPN client.

Do I have to configure some NAT ? Do I need to configure some rules to let the vpn ip pool go to the internet.

I just want my remote users to navigate on internet through the vpn tunnel and the remote gateway (the asa).

Any hints ? Do I have to setup some proxy ?

Thank you so much !
Hi experts,

I have a rather complicated problem which I am trying to debug.
We are using a proxy server (squid) for user authentication. We are trying to use Kerberos authentication and it works on our test systems without any problems.

On the production machine however, it fails and always falls back to NTLM authentication (on all browsers). We could find out that the system does not even try to use Kerberos.
The production machine is a windows server 2012 R2. If we look at the outpout of klist, we see no tickets for HTTP/Proxy.domain. However, we can succesfully obtain the tickets using klist get HTTP/Proxy.domain - but that ticket will not be used afterwards.

What we are looking for, is a way to debug this. Enabling LSA/Kerberos-Logging (setting SPMInfoLevel) did not reveal anything useful.

squid/3.3.8 @openSuSe 13.1 (x64), using the built-in Kerberos authentication helper, the Proxy Server is domain-joined, SPN is set correctly.
I have perviously (october 2013 actually with this guide set up Loganalyser with mysql and rsyslog to receive log information from vmware vsphere hosts and store them. This has been running for some months. When I enter the webpage at http;//hostname/loganalyser I get the information below;

No syslog records found - Error Details:
No syslog records found

Logstream Warning
While reading the logstream, the php script timeout forced me to abort at this point.

If you want to avoid this, please increase the LogAnalyzer script timeout in your config.php. If the user system is installed, you can do that in Admin center.
I then start by checking the configuration and various outher troubleshooting steps shown below:

# more /var/www/html/loganalyser/config.php
(pasting relevvant information)
$CFG['UserDBEnabled'] = true;
$CFG['UserDBServer'] = 'localhost';
$CFG['UserDBPort'] = 3306;
$CFG['UserDBName'] = 'rsysdb';
$CFG['UserDBPref'] = 'logcon_';
$CFG['UserDBUser'] = 'rsyslog';
$CFG['UserDBPass'] = 'password!';
$CFG['UserDBLoginRequired'] = true;

$CFG['DefaultSourceID'] = 'Source1';

$CFG['Sources']['Source1']['ID'] = 'Source1';
$CFG['Sources']['Source1']['Name'] = 'My Syslog Source';
$CFG['Sources']['Source1']['ViewID'] = 'SYSLOG';
$CFG['Sources']['Source1']['SourceType'] = SOURCE_DB;
$CFG['Sources']['Source1']['DBTableType'] =
Solaris is installed on a VMware virtual machine.
After installation I installed VMtools to add VMXNET3 virtual NIC.
I also have second physical NIC E1000g that I cant plumb, it says that the interface is not found.
I used these manuals to setup the virtual NIC and to define network properties:

I can see the VMXNET3 NIC and my network configurations (IP, Default GW,Subnet) , I can send ping to my IP and default gateway but I can't ping to othe computers.

please help
The USB boots directly into linux with no menu.  No "Do you want to install Linux" nor "Do you want to try Linux" nor "Do you want to multiple install" nor "Do you want to checkdisk".  None of that.  You boot up from the and you end up at a desktop or a terminal window.  

B)  It has SSH server built into it so that when the system boots up it is ready to accept SSH connection.

C)  It is persistent in that if I add a user it will remember that I added that user and password the next time I reboot.

D)  Basic utilities like ping, traceroute, curl, ssh, telnet will be on there.  

That's it!  I have a Windows 7 system or an Ubuntu laptop from which I can create the USB.  What USB utility plus what distribution of Linux will get me to my needed bootable USB?

I have the following problem:

I have a website that runs in a internal website on my company, but some pages inside my website requires internet, my problem is that i can't configure my server to have access to internet using the proxy settings. I need that the server have access to internet to process these pages inside the website. I review about 20 websites, but anyone provides me a solution that works, also try cntlm but anyone explains how to install properly so i do what can i do and don't work. What is the step by step process to do a proxy setting configuration in the server? Thank You!
I recently installed SmokePing on a server at work, so that I could monitor the state of our Internet connection to the cloud providers we use.  However, I'm having some trouble figuring out the meaning of the graphs that SmokePing generates.  For example:

These five graphs cover the same 24-hour time period.  The bottom-right host (labeled "Frontier") is the next hop after our default gateway.  The other four hosts correspond to four cloud services we use.

What might cause the transient hump to appear for three hosts, but not the other two?  Also, what might cause the small, sudden step-wise increase in latency, followed by a decrease later?  Finally, is this type of behavior fairly normal, or is something amiss?
Hi all!

I have an old mac mini g4 (single ethernet) with debian on it.

I am very happy with it but, being also my download station, I want to be able to limit its bandwidth regarding internet.
Also updates and backups kill my network (main problem in upload).

I've read about wondershaper and similar tools but I don't want my server to be slow on LAN, just on the Internet.
Is there any way to achieve this?
Hello Experts,

This is been a long unsolved question in my mind, I want to replicate a installation like Ubuntu or Fedora with my Linux from scratch7.4

I have the tar which holds nesscary file to boot up a system.

But the real problem is i want to push the tar file into another system via CD or USB and make that new pc to boot it from LFS7.4.

How to accomplish this.

I just need to be able to SSH to this device and run basic networking commands - ping, curl, traceroute, dig, etc.  I will be running it off of a USB - creating it with linuxliveusb.  What would be a solid basic gui-less distro that would work?
I am in a network that linux hosts with multiple interfaces ( prod, backup, management ).

We have to manually route off the linux box to multiple gateways.  

How do I find duplicate routes, bad routes ect ?

redhat 5+

I need to be able to identify that a visitor, visiting my site is using the correct DNS Settings.  Is there any method / script to confirm this.

Some of our e-mails have been removed and i need to recover them. I need to take an old backup and restore it into ClearOS. Specifically i need to restore the e-mails that are missing. How do i do this?
We have several servers and they were deployed with hard nfs mounts.  

If you comment out nfs in /etc/fstab; reboot them; log in and mount the nfs mounts manually the system works fine.  

If you don't  comment out nfs in /etc/fstab; reboot them; the systems take forever to boot ( 20 minutes or more ).  

Reengineering these system to softmounts is not an option.

I am looking for a solution that will check the systems and then mount the hard mounts.  

what needs to be checked and what are the commands for them ?

do I need to check both sides of the nfs hard mount ?

Oh, Redhat 5/6, physical servers ( virtual in the future )

I can't seem to find a decent example of how to use the tcpdump with the following parameters.

tcpdump [ipaddress] [interface] [port]

Any assistance is welcome.

Thank you.
Hi Guys,

I had to move a PCI nic card on my machine to accommodate a video card. Unfortunately the nic no longer works...

When i run ifconfig I get the error:

Bringing up interface eth1:  Error: No suitable device found: no device found for connection 'System eth1'.

Please see attached ifcfg-eth1 and the 70-persistent-net.rules files. I've also tried renaming the 70-... file but that made no difference.
I have two Red Hat Enterprise Linux 6 systems that are both on the same network:

HOST1 - Snort Sensor -
HOST2 - MySQL Database Server -

I need to make the Snort sensor write to the database via an ipsec tunnel.  I have the tunnel created using openswan using these instructions:

Now I am wondering how do I force all MySQL traffic through the tunnel?  Any help would be appreciated.

Linux Networking





The variety of Linux distributions creates myriad issues relating to configuration and operations when computers are networked, not the least of which is the use of various network management applications, some of which are included with specific distributions, while others are standalone applications.

Top Experts In
Linux Networking