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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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I have a loopback traffic in linux involving port 631 and I have no idea what is causing it

So I did some packet capturing in my networking and everything else is actually fine except for this weird communication where source and destination is literally 127.0.0.1, source port is 631, and destination port is a continuously incrementing…
cmakeislife
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Loopback adapter cannot connect to the domain network

I am working on a project creating Microsoft Print Server Farms with High-availability. It works perfectly with the Loopback adapters in the servers and a network load-balancer. The Loopback adapters are configured with the same setting and the ip…
Howard2119
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Calculate pm2 ram consumption on basis of hit or traffic

I have deployed loopback backend application in ec2 instance. I am using Pm2 server. How can I calculate ram and cpu for traffic or hit ?
MD. Ashfaqur Rahman Tahashin
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Network loopback device missing in Ubuntu 14.04

I want to program an FPGA via JTAG and the xmd script connects to 127.0.0.1:3121 to do so. That worked nicely for months. After a reboot this connection suddenly didn't exist any more, I cannot ping 127.0.0.1 or localhost (still resolved to…
Martin
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ip command equivalent to `ifconfig lo x.x.x.x up`

I am trying to set bind loopback to an IP address with ip link set lo 10.254.254.254 up but keep getting the error Error: either "dev" is duplicate, or "10.254.254.254" is a garbage. I googled the error, but there isn't any consistency in the…
dhuyvetter
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Add second ip to loopback on Centos

We currently run Suse servers and add the following to the loopback interface: vi /etc/sysconfig/network/ifcfg-lo # Loopback (lo)…
rezizter
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A looped hub connected to a switch

---- We don't want to block the use of Hubs --- If two switches are connected to each other via a hub, STP detects and blocks alternate link (if available). But if a hub is connected to even one (single) switch, and the hub is LOOPED TO ITSELF, it…
Nurhak Altin
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iptables dnat not working for https

I have an http server listening on ports 8080 (http) and 8081 (https) on 127.0.0.1 I have these iptables rules to redirect from/to $external_ip: iptables -t nat -A PREROUTING -i eno1 -p tcp -d $external_ip --dport 80 -j DNAT --to-destination…
morgano
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Why adding external IPs to loopback (lo) works just like adding to ethX

For ages(>7yr) my automation scripts were adding new external IPs to the servers in this way ifconfig lo:0 11.22.99.44 netmask 255.255.255.255 ifconfig lo:1 11.22.33.44 netmask 255.255.255.255 ... This worked fine with all (>10) providers i…
Alexander lazutov
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using ethernet ipv4 as internal bus while allowing the full ipv4 address range for the external interface

We have designed a device to be used as one device, but using ethernet ipv4 inside to communicate with internal not linux-based ipv4-speaking peripherals, juste like what we could do using pci or usb, for example. Now comes the problem that the…
Philippe De Muyter
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Server with slow ping response

Two boxes with identical loads serving the same sites tend to slow down and stop responding to ping. The slow (or intermittent) ping causes our load balancer to think the servers are offline and disable them. There is a third server with identical…
Joel
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Ubuntu rename loopback interface

I have a Linux box with Ubuntu 16.04. I've noticed some odd behavior when I needed use the loopback interface. So I checked with ifconfig first and it showed that: rename1 Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 …
northway
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How to create image file and mount via. loopback (Ubuntu to remote backup space)

I've been fiddling around with the Hetzner Backup Space and I want to use rsync via. rsnapshot in order to back up my files (more info at their Wiki here) They state in their documentation: The direct use of rsync is not possible. Backup space can,…
Arni J
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Slow "ifconfig lo"

How can I diagnose a slow loopback interface? Here is what I see on my Fedora23 box: $ time ifconfig lo lo: flags=73 mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10 …
mss
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Network Traffic fluctuating, even with loopback

I am using iperf tool to benchmark my network interfaces on two identical machines (Dell Blade Server M620). Both have given different results. On 1st machine, I ran server and clients as: Server ==> iperf -s -B 172.17.250.200 Server listening on…
Waqas
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