Are the following statements in /etc/network/interfaces equivalent?  allow-hotplug eth0   and..  auto eth0 allow-hotplug eth0   That is, does allow-hotplug do everything that auto does and more?
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I understood the very basic concept of how to use /etc/network/interfaces, but all I find online are examples, example after example, which I can copy-paste from. What I miss is an explanation of the syntax, an explanation of the meaning of the commands and which order the commands require. I want to understand, because most of the time copy-paste is not enough, because I'm not working on a fresh machine, so I can't just overwrite existing configurations because it would break a lot of stuff. man interfaces was not very helpful since it is written very complicated.  Example questions I have: what does inet in an iface line mean exactly (I could not even find it in the manpage), what does manual in an iface line mean exactly (many examples use it, but according to manpage it needs an extra config file then, which the examples don't present), when do I use or need them? When not? When I create a bridge, what exactly happens to the interfaces?
99651
The /etc/issue of my Debian testing references : stretch, which is supposed to be testing, and sid, aka unstable. What does that mean? That I have a mix of packages from the two of them?  $cat /etc/issue Debian GNU/Linux stretch/sid \n \l
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I've always used the ifcfg-eth0:1 alias files to create additional addresses. However, in , it states that:     As the ip command of the iproute package now supports assigning multiple address to the same interface it is no longer necessary to use this method of binding multiple addresses to the same interface.    Furthermore, numerous answers and comments on this site mention that ifconfig is deprecated and that "ip" should be used instead.  I'm fine using it for live changes, but how do I persist the changes across reboots without using the alias files?
118305
My question is basically the same as .  I have two interfaces eth1 (10.0.0.2) and wlan0 (192.168.0.2). My default route is for eth1. Let's say I want all https-traffic to go through wlan0. Now if I use the solution suggested in the other question, https traffic will go through wlan0, but will still have the source-address of eth1 (10.0.0.2). Since this address is not routeable for the wlan0 gateway, answers won't ever come back. The easy way would be to just set the bind-addr properly in the application, but in this case it is not applicable.  I figure I need to rewrite the src-addr:  # first mark it so that iproute can route it through wlan0 iptables -A OUTPUT -t mangle -o eth1 -p tcp --dport 443 -j MARK --set-mark 1 # now rewrite the src-addr iptables -A POSTROUTING -t nat -o wlan0 -p tcp --dport 443 -j SNAT --to 192.168.0.2   Now tcpdump sees the outgoing packets just fine and ingoing packets arrive for 192.168.0.2, however they probably never end up in the application, because all I ever get to see, is that the application is resending the SYN-packet, although the SYN-ACK was already received.  So I thought, maybe I need to rewrite the incoming address too:  iptables -A PREROUTING -t nat -i wlan0 -p tcp --sport 443 -j DNAT --to 10.0.0.2   but that didn't work either. So I’m kind of stuck here. Any suggestions?
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I tried to use  sudo service networking restart   and  sudo /etc/init.d/network restart   but they both crash the window manager and I can no longer use my keyboard for input into X.  when I use the /etc/init.d/ method it complains saying that I should use the service utility  e.g. service networking restart   but it crashes just the same.  Is there a GUI method of restarting networking?
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It's very annoying to have this limitation on my development box, when there won't ever be any users other than me.  I'm aware of , but none of them do exactly what I want:    (The version in Debian testing, 1.0, only supports IPv4)  (the "nat" table is not yet implemented for ip6tables, the IPv6 version of iptables) sudo (Running as root is what I'm trying to avoid) SELinux (or similar). (This is just my dev box, I don't want to introduce a lot of extra complexity.)   Is there some simple sysctl variable to allow non-root processes to bind to "privileged" ports (ports less than 1024) on Linux, or am I just out of luck?  EDIT: In some cases, you can  to do this.
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Is there a way to block all normal ftp traffic, and only allow the sftp protocol in sftp?  edit:  sorry my bad!  for secure ftp i must use the ftpes protocol...
61830
I am using Ubuntu 12.04.  My /etc/network/interfaces file consists of:    # The loopback network interface   auto lo   iface lo inet loopback     # The primary network interface   auto eth0  iface eth0 inet static   address 192.168.1.58   gateway 192.168.1.1 network 192.168.1.0   broadcast 192.168.1.255 dns-nameservers 66.212.63.228 66.212.48.10     I ran the command: /etc/init.d/networking restart  Which responded with:   *Running /etc/init.d/networking restart is deprecated because it may not enable again some interfaces   *Reconfiguring network interfaces...   RTNETLINK answers: File exists   Failed to bring up eth0   [ OK ]     Next I ran ping google.com and received:    ping: unknown host google.com   I am not sure if my interfaces refreshed. How do I properly configure my network with my static DNS addresses?
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Why is one preferred over the other in this example?  sudo su echo "options iwlwifi 11n_disable=1" &gt;&gt; /etc/modprobe.d/iwlwifi.conf exit   Please provide links to Ubuntu documentation.
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Let's say I have two active network connections that let me out to the internet.  I want certain applications to only use Network Connection 1, while some others should use Network Connection 2.  Is this possible in Windows XP? If so, how can it be done?
103063
I was putting the following in /etc/sysctl.conf in Ubuntu 16.04 and ipv6 was disabled.  net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1   In Ubuntu 18.04 I have to add the following to grub.  GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1"   Just wanted to have confirmation whether this is the new way in Ubuntu 18.04 to disable IPv6.
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If I enter for example "block 59.164.0.0/20" as a firewall rule.  Does that mean it blocks the IPs 59.164.0.0 to 59.164.0.20 or does it mean something else ?
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Fist let's block all Incoming, Outgoing signals  via iptables.     vi /etc/sysconfig/iptables   *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A OUTPUT -j DROP -A INPUT -j DROP -A FORWARD -j DROP COMMIT   start iptables:   service iptables start   My Ethernet Cable is plugged in. let's try something via terminal  ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.   that is all. just 1 line. after that it stalls. clearly iptables is blocking it successfully  now I am going to disconnect my Ethernet cable. my internet is disconnected.  let's try it again:  ping 8.8.8.8 connect: Network is unreachable   this time .. instantly.. it returns that message.  Clearly, weather it is "ping" or any other program.. it is determining if a network interface is up or not before it executes it's internet command.  of course soon as it executes.. it is not able to pass through iptable rules. but what seems evident is.. it does not first consult to the iptables..  it first checks to see if a network interface is connected or not.   I would like to figure out how I can manually let it know that network interface is connected.  in other words unless I tell it network interface is up.. it should simply behave the same way it behaves when network interface is not connected ( when the ethernet cable is not plugged in)  how can this be done ?
90022
Is it possible to tell your router to redirect specific domains to a specific IP? The router is an Airport Extreme, unfortunately. If it can't be done with this specific router, is there another way to achieve this?
91963
My /etc/ssh/sshd_config file has a line like:  AllowUsers jim@11.22.33.456   If I want to allow jim to use another IP addresses, how do I specify it?   Does it take the form of a comma separated list? Or, do add a similar line like   AllowUsers jim@new-ip-address   ?
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There is a directory in System/Library for startup items I presume: StartupItems  I need to have a shell script that will configure ethernet interface at start up, with local network address and subnet mask. I need to do this because the network preferences for configuring the ethernet interface will NOT set it using manual settings. THIS appears to be a serious bug, or my installation is bad.  I was given the advice to use  networksetup from the command line but that will not configure the ethernet interface in such a way that the configurations will be there on reboot.  The script needs to do its work with root privileges, or with sudo, but I am assuming that if it uses sudo, there will be a password dialog presented at boot time when the boot process gets to that script.  (I have had enough experience with FreeBsd and Linux to find my way around in the terminal, but not necessarily as it applies to Mac OSX)
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... but still be required for applications that need admin privilegies?  In order to allow the following:  $ apache2ctl restart httpd not running, trying to start (13)Permission denied: make_sock: could not bind to address 0.0.0.0:80 no listening sockets available, shutting down Unable to open logs  $ sudo !! sudo apache2ctl restart             #no password asked $                                   #works!   For reference I've seen this setup on amazon's e3 instances  Any idea?