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Is there a htop/top on Linux where I get to sort processes by network usage?
NetHogs is probably what you're looking for:
a small 'net top' tool. Instead of breaking the traffic down per protocol or per subnet, like most tools do, it groups bandwidth by process.
NetHogs does not rely on a special kernel module to be loaded. If there's suddenly a lot of network traffic, you can fire up NetHogs and immediately see which PID is causing this. This makes it easy to identify programs that have gone wild and are suddenly taking up your bandwidth.
Since NetHogs heavily relies on /proc, most features are only available on Linux. NetHogs can be built on Mac OS X and FreeBSD, but it will only show connections, not processes...
Also iftop:
display bandwidth usage on an interface
iftop does for network usage what top(1) does for CPU usage. It listens to network traffic on a named interface and displays a table of current bandwidth usage by pairs of hosts. Handy for answering the question "why is our ADSL link so slow?"...
iptraf is my favorite. It has a nice ncurses interface, and options for filtering, etc.
jnettop is another candidate.
edit: it only shows the streams, not the owner processes.
ntop or nagios
Check bmon. It's cli, simple and has charts.
Not exactly what question asked - it doesn't split by processes, only by network interfaces.
Another option you could try is iptstate.
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Let's say I have a 100G disk which i want to expose as an ISCSI-target and I have configured 2-ISCSI-portals(IP1, IP2) which can be used to access the ISCSI-target
Note: I have used more than one portal for my High-Availability Use-cases
Let's say, From the Host, I have used IP1 for the login to the ISCSI-Target and am able to connect to the target successfully. After some time Say, because of some reason IP1 is down.is there a config/way to specify the ISCSIADM to fall back to IP2 for connecting to ISCSI-target
As stark says in the comments above, the answer is to use dm-multipath. There are numerous articles on how to set this up, but the short answer is that it'll likely "just work".
First, install multipathd on your system. Then, when you use iscsiadm in discovery mode, so long as your iSCSI target reports both portals, Linux is going to connect to both portals. You'll get two block devices, both with the same SCSI WWN. Multipathd wakes up, sees the two devices with the same WWN, and bundles them into a /dev/dm-X device for your use. From that point forward, multipathd manages the paths according to how you've configured its policy. The default may be fine for your use.
The key point here is that iscsiadm and iSCSI are kind of "out of the way". You'll have a session for each path. The sessions may come and go. DM-Multipath manages which sessions are involved in providing access to your LUN.
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I'm on Linux Mint, never connected to the internet for weeks, and still not connected, doing some python programming (Python 3.6).
I happened to look at the firewall program in it 'report' section and see this
(please not that the firewall was actually set to ALLOW outgoing until I changed it just before this screenshot (it was only set to block incoming). Again, to my knowledge I am not, and have not, been connected to the internet at all and my networking is turned off.:
I'm not a network programmer, but this seems to be showing that these applications have been accessing network ports, correct?
Why would python 3.6 (which I was using) be on this list or ever need to connect to any port at all?? Am I looking at nefarious activity here?
I've heard that software can be placed directly on the hardware of a system. IS it possible that my network interface card could be activated and used without giving any indication?
And again, why would my python 3.6 application be on a firewall report at all?
I'm very concerned about this. Can someone enlighten me?
What you are looking at are mostly servers that are listening for incoming connections. That certainly covers ntpd, cups, ntpd.
It looks like some python programs have also been listening for connections, maybe as part of your programming exercises.
The fact that programs are listening for incoming connections doesn't mean anything has actually connected to them, or even that anything could.
An address of "*" indicates that it's a potential connection, not an actual connection that happened.
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I set up a virtual machine with Ubuntu Server edition.
When I boot it up, the output from the console appears on VirtualBox's virtual screen. This means the machine is wasting resources trying to display output on a screen. It's just a text terminal, I know, but it still requires resources. Why waste them when I'm going to only access remotely through PuTTY?
I know that VirtualBox can start a virtual machine in "headless" mode, but I fear it will just disable VirtualBox's output window, with no real impact on the virtual machine itself.
My questions are:
Will my virtual machine still detect a monitor attached when it runs in headless mode?
If so, how big is the performance impact of this situation? Is there any way to avoid it?
It does not require any additional resources. Just a tty device and a blocking getty process which requires no CPU resources and which has would both have been created anyway. (Every Linux system that I know starts 6 ttys by default).
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I have a Linux box wich has several 10 Gbe interfaces. What I want is to make a crypto-tunnel that has an ability to process 10 Gbit/s traffic as well as 10 Gbit/s router/firewall. There are some ways to achieve this but as I see it all the ways are brings to user-space or kernel-space processing.
As for the user-space solution, I suppose TUN/TAP device. But my experiments shows me that single TUN-device has performance limit at 1 Gbit/s boundary. I try some kind of TUN's aggregation and it gives me about 3.5 Gbit/s on 8xCPU XEON configuration (w/o encryption thought)
As for the kernel-space solution, I suppose that it might be faster than user-space, but it has another degree of complexity....
Has anyone has knowledge of how to make 10th Gbit/s Linux-based VPN solution?
UPD #1
Software solution wanted
TOE (TCP Offload Engine) is both your friend and enemy here.
TOE is the network card equivalent of a GPU from a graphic card along with something like DMA (Direct Memory Access) used by old style hard drive controllers. It allows for offloading the work of the TCP/IP stack to the NIC instead of running it through motherboard front side bus and CPU which are bottle necks for data being processed at this speed.
In order for what you are asking to work you will need your 10Gbps cards to have TOE (hardware acceleration) enabled in the OS and drivers. I worked on a project similar to this using a Cisco Nexus switch and some $5500 NIC cards about three years ago so I'm a little out of date on the technology. I'm betting things have moved along and costs gone down.
If you have already solved the TOE issue, then ignore my response.
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I know both are IPSEC stacks in Linux kernel and that KLIPS is older and Netkey is newer but other than that I find no other documentation of them. I want to know the real technical differences between them. Is there any one here who can tell me the difference or share some documentation source?
Any help would be appreciated.
From the article linked by shdobxr, the most relevant part regarding the difference between KLIPS and Netkey seems to be the following:
When you apply firewall (iptables) rules, KLIPS is the easier case,
because with KLIPS, you can identify IPsec traffic, as this traffic
goes through ipsecX interfaces. You apply iptables rules to these
interfaces in the same way you apply rules to other network interfaces
(such as eth0).
When using NETKEY, applying firewall (iptables) rules is much more
complex, as the traffic does not flow through ipsecX interfaces; one
solution can be marking the packets in the Linux kernel with iptables
(with a setmark iptables rule). This mark is a member of the kernel
socket buffer structure (struct sk_buff, from the Linux kernel
networking code); decryption of the packet does not modify that mark.
Writing in 2014, all linux distros should now come with a kernel that support both KLIPS and Netkey.
http://www.linuxjournal.com/article/9916
This is by far the best break down of a VPN setup with either. You should be able to deduce what you need for this article.
Good luck!