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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 ...

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Altering the speed of the loopback interface on Windows 10

When running network performance tests using iperf3 within powershell against the loopback interface, I max out around 12-13 Gbits/sec, as measured by the network activity within the Windows10 ...
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139 views

Add-NetNatStaticMapping not port forwarding to local VM

I'm running windows 10 build 1809 and have hyper-v installed. I have a Linux machine running behind a NAT with internet connectivity working on IP 10.0.5.5. I basically followed instructions on the ...
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reasons for fastpath sockets to fail?

I have a windows 2012 server that refuse to open TCP fastpath connections. The code that opens it do all the possible tests in every step on the road and it doesn't have any errors (it also works on ...
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Can't run loopback app with DataPower through API Designer

I'm new at IBM Api Connect, and Loopback. I followed this tutorial I installed nodejs v6.12.0, npm v3.10.10, API Connect: v5.0.8.4-iFix (apiconnect: v2.8.29), docker-compose version 1.22.0, build ...
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60 views

Microsoft KM-TEST Loopback Adapter Throughput Cap

Got a server that we're configuring Anycast on, and instead of a secondary NIC we're trying a loopback adapter, however the Microsoft KM-TEST loopback seems to be capped at 1.2Gbps. Anyone have ...
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Does Loopback able to support all TCP/IP protocols

Does a Windows loopback adapter supports ACD and duplicate IPs. Say we have a code that supports full TCP stack and we bridge the program to loopback using PCAP. If in case I set both the address ...
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111 views

How can I count / view all fast-path sockets on windows server?

In case you're not familiar, fast path loopback sockets: https://blogs.technet.microsoft.com/wincat/2012/12/05/fast-tcp-loopback-performance-and-low-latency-with-windows-server-2012-tcp-loopback-fast-...
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2answers
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Windows Loopback adapter not participating in local network

I have created a Windows loop back adapter with 'Obtain IP address Automatically' enabled. ipconfig /all Ethernet adapter LL Address: Connection-specific DNS Suffix . : Description . . . . ....
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1answer
123 views

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 ...
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1answer
102 views

Corosync cluster will not bind vips to loopback, so apache fails to start in CentOS 7

I have a problem getting apache to work in a corosync cluster. I probably sifted through more than hundred web pages and a couple of dozen Google Searches, and was not able to find any matching ...
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242 views

How can i add a second ipv6 loopback address in centos7?

How can I add a second ipv6 loopback address in centos 7.4? I added the first loopback address to /etc/sysconfig/network-scripts/ifcfg-lo with ipv6init and ipv6addr_secondaries: IPV6INIT = yes ...
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How can I give access to loopback devices which are created dynamically to a Docker container?

I have a small Docker container from which I can access /dev/loop0. For this I've added to docker run: --device=/dev/loop-control:/dev/loop-control \ --device=/dev/loop0:/dev/loop0 \ On this ...
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1answer
581 views

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) configuration IPADDR=127.0.0.1/8 IPADDR_2=192.168.0.91/32 NETMASK=...
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136 views

Prevent NginX from listening upon `127.X.X.X/8:PORT` while it is listening to `0.0.0.0:PORT`/`*:PORT`

I have an NginX instance setup/running as my web-facing/front end server. I have it configured to listen for traffic upon all IP addresses on the 80, HTTP, and 443, HTTPS, ports e.g. listen 80; and ...
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1answer
274 views

Nat Loopback - Access external IP from internal

I have a static IP and I've made a webserver that is running fine from WAN (domain points to my IP). However, when I access my external IP/Domain from my LAN, it redirects me to my router login page. ...
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1answer
585 views

Err-disable in Switch 2960 [closed]

I have a problem. I have a Cisco 2960, this switch conect 23 Macs. The problem is that a pc puts the port in err-disable. When I put the command "show interfaces status err-disabled" the output is ...
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Kubuntu 17.04 on VM: loopback interface routed “outside”

Disclaimer: Yes, I know my problem description might be not very accurate and my terminology as well. Can not change that since I am new to this topic and do not know it yet. But I apprechiate ...
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1answer
216 views

How to change loopback network mask or redirect subnet to another interface [closed]

I have the following problem. First of all. Here are my interfaces. # ip addr ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd ...
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105 views

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 (...
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2answers
1k views

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 $...
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2answers
764 views

Heavy TCP traffic on loopback

While trying to generate some test traffic on my loopback interface, I noticed there was so much noise there that the output from Wireshark was essentially useless, with tons of SYN/RST, ACK packets ...
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2answers
785 views

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 ......
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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 ...
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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 ...
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2answers
72 views

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, ...
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1answer
851 views

Is it important to use localhost/127.0.0.1 rather than machine's own IP address?

I'm on Amazon AWS EC2 running Amazon Linux, though that may not be significant to the answer. Say I have three hosts, H1, H2, H3, with private IP addresses of 10.0.0.1, 10.0.0.2, and 10.0.0.3. This ...
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1answer
369 views

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 ...
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1answer
565 views

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 ...
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297 views

Why and How to set Public IP on Loopback Interface

I been using this forums for many years and this is the first time im in need to open a question, i search across the internet but i could not get an specific and clear answer, probaly because i dont ...
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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 ...
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181 views

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<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 ...
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1k views

Server send TCP ACK with wrong number after receiving SYN

I have a client establish new TCP connection then sends request to a server per second. Both client and server are on the same linux box (via loopback interface). The client periodically reports ...
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333 views

Two loopback adapters communication in windows 7 or 8

Once our development systems are upgraded from windows XP to windows 7, my debug setup has stopped working. Steps followed in original setup (Windows XP): Add two loopback adapters Assign ipv4 172.16....
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1answer
9k views

Centos 7.1 Create Loopback Interface [duplicate]

I'm trying to alias an ip address onto Lo or create a new loopback interface such as lo:1 I've created /etc/sysconfig/network-scripts/ifcfg-lo:10 DEVICE=lo:10 IPADDR=192.168.10.1 NETMASK=255.255.255....
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3answers
2k views

Why only a single loopback address on IPv6?

IPv4 allocates a whole block of IPv4 loopback addresses, 127.0.0.0/8. IPv6, in contrast, only allocates a single loopback address, ::1. This seems surprising that IPv6 would be so stingy in its ...
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105 views

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 ==>...
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1answer
1k views

Loopback Processing Merge Mode

I am part of a team of IT Engineers who are currently revamping a large organisation. The previous IT department had some Group Policy objects in place for installing software(s), applying security ...
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0answers
152 views

Why is the loopback device needed on a client side of Stunnel?

This SANS Institute guide states that "On the client side, a port listening on the loopback interface of the local system would send/receive data on the clear-text protocol and tunnel out on ...
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1answer
301 views

Why does 0.0.0.0 resolve to the loopback device?

Why does 0.0.0.0 resolve to the loopback device? $ curl --verbose 0.0.0.0 * Rebuilt URL to: 0.0.0.0/ * Hostname was NOT found in DNS cache * Trying 0.0.0.0... * Connected to 0.0.0.0 (127.0.0.1) ...
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2answers
513 views

Terminal Server and loopback address usage

Been trying to research this question to no avail yet!. Perhaps somebody can help. I am trying to identify if localhost on a TS works in the same way as a straight server. If I have an application ...
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2answers
563 views

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 ...
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1answer
2k views

Forwarding a port on the loopback interface to a remote IP/port

I have two Docker containers that I'm trying to network together in a specific way. Container A is running a Redis server on port 6379. Container B is running an interactive shell and needs to access ...
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767 views

How to create another loopback interface on linux?

And NO: i don't ask about virtual IP. I need 2 different devices lo1 and lo2 to define different mtu and qdisc on them. Thanks.
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1answer
514 views

Is there a Universal/Generic Default Gateway Address in IPv4? [closed]

Is there a universal and/or generic default gateway address in IPv4? I'm looking for something similar to the way you can always reference a NICs IP address from itself with 127.0.0.1 regardless of ...
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2answers
720 views

how to force linux to accept packet with loopback ip

i have an embedded system with an Ethernet interface that needs to accept external packets with IP of 127.x.x.xx. is there a way to force Linux to accept external packets with this loop back address ...
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283 views

2 Webapps hosted on same server talking to each other - do they use eth1 or lo1?

I am trying to establish bandwidth needs for a set of webapps in the company. I am using SNMP to monitor the bandwidth on the eth1 interface, however I am trying to establish what is going over the ...
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1answer
491 views

My lo interface is down on boot. What can I do?

My lo interface is down when the system boot. I can turn it up with ifconfig up lo but I wonder what could be the cause? Where can I look to debug such problem?
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1answer
266 views

Is it possible to limit output bandwidth between eth0 and lo?

I'm trying to limit the bandwidth between my eth0 output (nginx proxy) to my loopback inteface (apache) by filtering on destination port. Incoming Packet -> Eth0 -> 0.0.0.0:80 Nginx -> tc ...
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1answer
601 views

server listening on loopback IP

I have a barracuda load balancer and a VIP which in turn forwards to a cluster of servers. Each of these servers has the VIP added to the loopback interface as the load balancer is on direct server ...
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1answer
231 views

Use of loopback Interface in iBGP

As I understand that the loopback interface(127.0.0.1) is used to route packets back to the source. How is it then used to talk to iBGP neighbors? I understand that the goal is to ensure that the ...