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Questions tagged [loopback]

In TCP/IP a loopback device is a virtual network interface implemented in software only and not connected to any hardware, but which is fully integrated into the computer system's internal network infrastructure. Any traffic that a computer program sends to the loopback interface is immediately received on the same interface.

In TCP/IP a loopback device is a virtual network interface implemented in software only and not connected to any hardware, but which is fully integrated into the computer system's internal network infrastructure. Any traffic that a computer program sends to the loopback interface is immediately received on the same interface.

A loopback interface has several uses. It may be used by network client software on a computer to communicate with server software on the same computer, namely on a computer running a web server, pointing a web browser to the URLs http://127.0.0.1/ or http://localhost/ will access that computer's own web site. This works without any actual network connection–so it is useful for testing services without exposing them to security risks from remote network access. Likewise, pinging the loopback interface is a basic test of the functionality of the IP stack in the operating system.

Source: wikipedia

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How do I force localhost resolution to be 127.0.0.1 instead of ::1?

I'm running Windows 10 x64 and I have a legacy application that doens't work fine with localhost being translated to ::1, but instead it works for 127.0.0.1. How do I force Windows 10 to resolve localhost to 127.0.0.1? I've already edited the hosts…
gremo
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TCP packets dropped in ipv6 loopback

Just logged in to a Windows host, I noticed an unexpected CPU usage. I quickly found out the processor was being hogged by the Windows firewall services. I enabled logging, and I started to see sheets after sheets of dropped TCP packets, with…
aledeniz
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Can't access server on loopback address, only on private address

I am running a rails web app server bound to 0.0.0.0 on port 80 like so: sudo rails s --port=80 --bind=0.0.0.0 I can access it at my private address http://192.168.0.13/, normally I can access at the loopback address http://127.0.0.1 /…
david_adler
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Adding a virtual NIC to a 2008R2 server makes internet unreachable, why?

I currently have a Windows Server 2008R2 box with a single physical NIC. For what I want to do I need two network adaptors in the box. To accomplish this, I added a legacy hardware device "Network Adaptor" and used the Microsoft Loopback Adaptor as…
Arvo Bowen
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Server hangs at "Shutting down loopback interface" on reboot

I'm having some trouble understanding what's going on with connecting one of our Xen hypervisors to our iSCSI SAN. Ever since we mounted our iSCSI targets, we've experienced hanging on reboots. This is what it looks like... Stopping iscsi: …
James
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route packets through hardware loopback interface, not lo

My embedded Linux board has 3 interfaces: eth0 - For all outbound traffic eth1 - A hardware loopback (traffic leaves board, but comes immediately back in the same port) lo - Standard loopback interface ifconfig reveals the following: eth1 …
Trevor
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Is it okay to copy an image file which is still mounted via a loop device?

I have a 100 GB image file which is created using dd. This image file is mounted via a loop device as read-write. I want to store a backup of this image file at a remote location. I have a script which compresses the image file (using zip) and…
Anjan
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ext4 loopback device, Buffer I/O Error on reboot

I am trying to mount a loopback device on my ext4 formatted ssd drive. I get these errors when I reboot on Linux kernel 2.6.38.8 Buffer I/O error on device loop1, logical block 0 Here is what I do: # dd if=/dev/zero of=/mnt/s/lodev bs=4096…
cvb
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What is the proper position for the loopback address in a DNS server selection list?

Best practices indicate that one should list 127.0.0.1 in the DNS list for the network adapter configuration for a Domain Controller, but not as the first one. With that said, what is the best place to put it in a list with more than two DNS servers…
Bigbio2002
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iptables DNAT from loopback

I'm trying to understand the limitations of using iptables DNAT with loopback addresses. Consider we have an application which can connect only to 127.0.0.1; the obvious solution to make server and client work on different nodes is to use NAT as…
artyom
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Boot Linux from a disk image on a Windows partition

I'd like to install Fedora 15 to a disk image on a Windows 7 partition, then boot from that image using the Windows 7 native boot loader. The advantage of this would be to avoid resizing the NTFS partition and the (small, granted) risks that…
badocelot
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HP switch 'mirror port' makes a Cisco switch port err-disabled due to keepalive loop-back

I'm trying to connect an HP ProCurve 5304xl switch to a Cisco 2950. The HP port I'm connecting to is described as a 'mirror port', which appears to be like a SPAN port except that it also allows ingress traffic. What I want is to push the traffic…
Matt Bennett
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Is adding servername as an alias for localhost/loopback correct?

On linux systems, I've seen many variations of /etc/hosts configurations with regards to the loopback address, localhost, and server aliases. Some include the servername as an alias for the localhost/loopback address (127.0.0.1), and others don't.…
nezroy
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XEN: Error: Device 769 (vbd) could not be connected. Failed to find an unused loop device

I'm trying to start a new DomU machine (Lenny) on an Ubuntu Dom0. However, I'm getting the following error when executing the xm-create command: # xm create vm3.rootspirit.com.cfg Using config file "./vm3.rootspirit.com.cfg". Error: Device 769 (vbd)…
Tuinslak
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How to prevent recursive windows when connecting to vncserver on localhost

I have a VNCServer (vino) configured on my Ubuntu 8.10 box. I would like to connect to this server from a vncclient running on this same machine (the reason for doing this strange thing is mentioned below). Understandably, when I connect to a…
Parag
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