Unanswered Questions
3,873 questions with no upvoted or accepted answers
10
votes
1
answer
2k
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Troubleshooting Redmine (Bitnami Stack) performance
I've got a Redmine instance (Bitnami Stack) that's unusually slow. Because I'm just trying to get to the bottom of this, I have some theories which I'd like to discuss here. So, if anybody has any ...
CommunityBot
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9
votes
2
answers
689
views
Cisco DNS doctoring or Hairpinning?
I've the following configuration: CISCO 881, IOS 15.2(4)M6. On WAN interface is configured the 86.34.156.48/29 subnet from our ISP. Behind the router is staying 2 webserver. NAT: 86.34.156.51 <> ...
- 3,096
8
votes
0
answers
3k
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DHCP interface never transitions to configured state in systemd
I have a server running CoreOS, and my main network interface that gets configured via DHCP gains a carrier and is routable, but never leaves the configuring state. This causes systemd-networkd-wait-...
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8
votes
1
answer
196
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Configure Juniper M320 as Ethernet/STM transparent converter
There is Juniper M320. We need to move ALL the traffic from one port to another. Everything that comes to one port goes to another and vice versa. No snooping or any other processing is required. One ...
- 2,898
7
votes
1
answer
258
views
Can network packet corruption affect only one server process out of many that are talking to the database?
Context
We saw sporadic ActiveRecord::StatementInvalid errors from MySQL servers over the course of 4 hours yesterday. The errors haven't happened since then.
Strangely, SQL statements seemed to ...
- 6,064
6
votes
1
answer
3k
views
Route host through a docker openvpn container
I am new to networking so I am trying this for the first time. I created an openvpn docker that connects to a VPN server. Running wget -q -O - https://api.myip.com inside the docker container confirms ...
- 101
6
votes
0
answers
2k
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meaning of 'event_wait : Interrupted system call'
I manage several OpenVPN links.
Sometimes while the VPN connection is UP for a few minutes/hours it suddenly gets down with the following (error) message:
event_wait : Interrupted system call (code=...
6
votes
2
answers
4k
views
Creating a virtual network for KVM guests spanning multiple host machines
I have 5 physical machines running Ubuntu 14.04, all of them are together in a network. These all have static IP addresses. Each of these machines has 1 to 4 virtual machines via KVM/QEMU running ...
CommunityBot
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6
votes
1
answer
2k
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Server 2008 R2 NIC in "Unidentified Network" state after connectivity loss is restored
I am having trouble with 2 servers, both with the same symptoms. When they are reconnected to the switch after losing connectivity, they stay in an "unidentified network" state. Only after cycling the ...
CommunityBot
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6
votes
0
answers
3k
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Why is the first of two post-up commands for routing in interfaces configuration not automatically processed
We managed to connect our servers to two distinct networks and everything works fine. We use routing rules that ensure that server responds to the right network.
I followed the instructions under ...
- 737
6
votes
0
answers
20k
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ActiveMQ - "Cannot send, channel has already failed" every 2 seconds?
ActiveMQ 5.7.0
CentOS release 6.3
java version "1.6.0_26"
Application server: Tomcat
In the activemq.log, I'm seeing this exception every 2 seconds:
2013-11-05 13:00:52,374 | DEBUG | Transport ...
- 51.6k
6
votes
1
answer
3k
views
docker network freezing randomly
Sometimes , all network's of my dedicate server is freezing (ssh also not working). it's randomly repeated.
OS: Ubuntu 14.04.3 LTS
On server installed docker containers, and i see in dmesg logs:
[...
CommunityBot
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6
votes
3
answers
215
views
How to make a disconnected drive?
kind of a weird question but how do I make a drive go from a OK state to disconnected state using net use? I do not want to delete it.
I am testing a script but the annoying thing is that to test the ...
- 6,860
5
votes
0
answers
2k
views
Ports exposed by docker container are shown as filtered - unable to connect
I am working on a fresh server installation of Ubuntu 20.04
I started a sample nginx by running docker run --rm -p 80:80 nginx
Port 80 appears to be open on the machine, I cant curl the nginx default ...
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5
votes
1
answer
10k
views
Adding a new DNS server with systemd-resolved
To access other machines on my network by their name, I have to add the following two lines to my /etc/resolv.conf:
search foo.local
nameserver 192.168.X.Y
But any changes I make do not persist ...
CommunityBot
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5
votes
0
answers
7k
views
How to bind a podman container to specific host IP
I need to setup a ssh server (actually a git repo) inside a podman container.
The host system has sshd already running on port 22.
I am creating a pod with following command:
# podman pod create --...
- 181
5
votes
1
answer
203
views
High Network I/O Between Docker Swarm Managers
Network Traffic
We run Docker Swarm with 3 manager nodes and 16 worker nodes. The network I/O between two of the three manager nodes is very high. To illustrate this, here is the output from iftop ...
- 27
5
votes
0
answers
666
views
Docker - Is it possible to create an IPv6-only bridge network?
Is it possible to create a custom bridge network that only has IPv6 address?
When I try to create a custom bridge network in the following way:
docker network create --driver bridge --ipv6 --subnet ...
- 51
5
votes
0
answers
2k
views
Is my NFS mount actually using async? Diagnosing very slow response time
I have the following NFS mount:
server:path /mnt/path nfs rw,hard,intr,nfsvers=4,async 0 0
Pings to the server are ~60ms, which is quite reasonable, yet any access to the mount is very slow. Copying ...
- 61
5
votes
1
answer
2k
views
How long is an (accepted) ICMP redirect observed for, and how can I shorten that time?
If a Linux host receives and accepts an ICMP redirect (accept_redirects=1 on the interface in question), how long is this route being cached for and observed? Can I lower that time?
I am asking ...
CommunityBot
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5
votes
1
answer
1k
views
How to debug failed checksums/flipped bits in TCP packets?
A web application we maintain recently encountered a very weird problem: three out of four virtual machines on two physical hosts had trouble connecting to the server of our payment provider via HTTPS....
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5
votes
1
answer
2k
views
Access to service in Docker container connected to VPN
I set up a Linux server (VirtualBox VM for now)
In that server I run a Docker container containing two things:
An app with web interface on certain port
Open VPN Client
I can access that app (from ...
CommunityBot
- 1
5
votes
1
answer
3k
views
Painfully slow network when routed through Windows 2012 R2
I have a Windows 2012 R2 server with two network adapters, on-board 1G one for the LAN and a 100M D-Link 530T connected to the internet. Internet Connection Sharing is set up on the latter. Client ...
CommunityBot
- 1
5
votes
0
answers
10k
views
How can I identify a rogue IPv6 DHCP server on my LAN?
This will be kind of a long post, but I want to give complete information.
I have a home/business LAN with isc-dhcp-server running an ipv4 dhcp server and bind as a DNS server running on an ubuntu ...
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5
votes
1
answer
5k
views
Windows 10 arp cache getting stuck after failed attempts when target machines are offline
After upgrading our development team to Windows 10 from 7, we are experiencing an issue with the ARP cache where a machine has the correct IP-MAC mapping cached, but the type is invalid due to failed ...
CommunityBot
- 1
5
votes
1
answer
1k
views
Can't communicate between multiple interfaces on same subnet
I have multiple ethernet interfaces on one machine, all on the same subnet. Normally these are set up to run on separate VM's, and I understand the limitations imposed by Linux as described here, but ...
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5
votes
0
answers
2k
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Is RSS (receive side scaling) in Windows considered unstable?
When asking a customer to enable RSS in their data center to improve network performance (very high UDP packets-per-sec rate), I was told that they generally turn it off, because after various ...
5
votes
0
answers
1k
views
IPSec bandwidth between two Pfsense hosts has predictable, variable bandwidth
I have a IPSec tunnel between two Pfsense machines. Both machines are connected to a 100mbps symmetrical connection. The latency between the two routers is ~70ms. I'm using AES-GCM-128 and SHA1, both ...
- 99.1k
5
votes
1
answer
657
views
Open Source Puppet for Network Devices
I'm attempting to determine whether I'd be able to run Puppet on network devices (switches, firewalls etc.). From what I can tell after reading online documentation, Puppet Enterprise will cater such ...
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5
votes
1
answer
2k
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keepalived config is not working correctly with virtualbox vms
my keepalived configuration is not working correctly.
I have two virtual testing machines (virtualbox) to try some things out with keepalived/vrrp. Bot can ping each other flawlessly (internal ...
CommunityBot
- 1
5
votes
0
answers
5k
views
Force Windows to use only TCP for DNS lookup
I have a broken (badly configured) VPN network that I cannot change. The remote gateway will route all UDP traffic for port 53 to a special DNS service. But I need to use a different DNS server also ...
- 392
5
votes
0
answers
4k
views
NAT64 configuration with tayga on Debian 6
I'm trying to implement NAT64 with tayga on my server and came to a point where I'm not sure how to proceed.
My server is connected via one IPv4 address and one /64 IPv6 address block to the internet....
5
votes
1
answer
2k
views
Getting 10mb/s speeds on a 1gb network
I'm at a loss and I've scoured the internet for answers, but none of them seem to work. I have a TP-LINK TL-SG108E 8 Port Gigabit Easy Smart Switch, a desktop, a laptop, and my new Synology 918+ that ...
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5
votes
1
answer
2k
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Enabling IPv6 with OpenVZ using Proxmox 2.2
I'm trying to enable IPv6 on my Debian nodes (OpenVZ) using venet; my host is under Proxmox 2.2 (kernel 2.6.32-16-pve), and it seems the routing fails.
My host correctly pings all my nodes; all my ...
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4
votes
0
answers
462
views
Linux VXLAN Hardware offloading
When looking at several guides to setup VxLAN networks on Linux there seems to be 2 options:
Open vSwitch (OVS)
Native Linux VxLAN device.
When using OVS there is an option to use vxlan encap/decap ...
- 1,539
4
votes
0
answers
11k
views
OpenVPN UDP error 10051 on Windows 10 clients
I am running an OpenVPN 2.4.9 server (without Access web interface) on a CentOS 7 machine for ~30 employees using Windows 10 laptops.
Recently, I noticed some people were disconnecting with UDP error ...
4
votes
0
answers
313
views
Mitigating a DDoS attack on a TOR server
Running a political blog over TOR network with a .onion domain name
I have been getting DDoS attack, I know how to mitigate an attack on clear net where the packets coming from normal IP addresses, ...
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4
votes
0
answers
2k
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How to set Rx Queue = N in linux / in Qemu / KVM?
I have configured 8 multiple queues on my CentOS VM box (running on KVM).
<interface type='direct' trustGuestRxFilters='yes'>
<source dev='ens113f0' mode='passthrough'/>
<model ...
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4
votes
2
answers
2k
views
Why is networkd changing the MAC addresses of my bonded interfaces?
When I add the config files below into /etc/systemd/network and restart systemd-networkd, I find that the MAC addresses of bond0, eth0 and eth2 have all been changed to a single, locally administered ...
CommunityBot
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4
votes
0
answers
111
views
Run a systemd timer only when network traffic is low
I would like to run a systemd timer daily, with lax time accuracy. However, I would want the timer to run only if the network is continuous idle/low load (for at least 2 minutes).
Is there any way to ...
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4
votes
0
answers
348
views
Interpreting WPR traces in trying to better network throughput
In trying to analyze a 3thparty application's throughput we have collected a WPR trace on two systems. One has Symantecs Intrusion Detection System enabled, the other one has not.
Following ...
4
votes
3
answers
4k
views
No connection to Azure Windows VM after reboot
We have a Windows Server on Azure, running flawless in the past year. After a Microsoft scheduled reboot/advisor recommendation, we lost access to this VM.
'Connect' (RDP) button on Azure portal does ...
CommunityBot
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4
votes
0
answers
2k
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Getting to enforcing google safe search using CNAME with unbound and nsd?
I am trying to implement this using Unbound and Nsd: https://support.google.com/websearch/answer/186669?hl=en
To force SafeSearch for your network, you’ll need to update your DNS. configuration. ...
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4
votes
0
answers
2k
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What is WebProxy/1.0 Pre-Alpha?
I have had 504 errors from my domain throughout the day. The back end servers look okay and the CDN provider (Fastly) doesn't think it could be them. Looking a little closer I see the following header ...
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4
votes
0
answers
565
views
How can I find the docker-machine network adapter name for a docker container?
I would like to introduce network variability into docker containers. Specifically, I would like to be able to run commands such as:
sudo tc qdisc add dev vethecb732a root netem delay 500ms 400ms ...
- 143
4
votes
1
answer
148
views
How to let chef listen on multiple IPs
I'm currently playing with chef to evaluate whether or not such a configuration tool might help us in our *nix-based environment.
For the last few days I'm struggling with one problem I can't find a ...
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4
votes
2
answers
746
views
How can I provide services to an internal air-gapped extranet
Background - "Extranet"
We have about a dozen users that are on what I would call an Extranet. It is an air-gapped LAN that is physically in the same location as our primary LAN. We share ...
CommunityBot
- 1
4
votes
1
answer
424
views
Windows port forwarding, local machine to server
I'm working on Windows 8. I'm trying to connect to an OpenStack cloud which is hosted on a remote server but has a public IP to the API. However, making API calls require calls to additional services ...
- 284
4
votes
0
answers
584
views
VLAN Communication between Cisco ASA 5510, and VMWare ESXi 5.5
I've having a problem, where my Cisco ASA 5510-v8.2 can't communicate with VM's in a VLAN specific port group.
The Cisco ASA is currently sitting in front of a group of VM's that have public IP's. ...
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4
votes
0
answers
272
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Breakdown Windows Network IO by network adapter and by process
What I'm trying to do is breakdown the Network IO by network adapter and by Process. The goal is to identify which processes are generating the most IO on a certain network adapter.
Resource Monitor ...
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