Newest networking Questions

Q&A for system and network administrators

SQL PaaS Network Security Configuration

We have a bastion host on which we have configured network security groups. The purpose is to connect with SQL PaaS using management studio. For the NSG tied to the bastion host we have defined two ...

Connecting two computers directly using Fiber

At my workplace, we have an electron microscope that is hooked to our storage server using a 10g FC connection. Due to unknown reasons, we are experiencing some issues with the connectivity. As plan ...

Client PC's constantly losing network connectivity

Good morning. We're running a SBS 2011 server and have 5-6 client PC's/Laptops running mainly Windows 10 but we also have a couple of Windows 7 machines. Currently we're experiencing an issue ...

Slow access to website; Packet capture is showing lots of TCP Dup ACK and out-of-order

So at work this issue has been going on for 14 days. We have routed the traffic to the server from multiple different sites from within out network but are getting the same slowness. The client will ...

Set IP address for virtual network interface

I have virtual interface tun0 connected to my vpn provider. I used the following commands to set it up with openvpn (route_up.sh): #!/bin/sh ip route add default via $route_vpn_gateway dev $dev table ...

Windows 2008R2 smtp traffic cannot leave the box

I have a weird situation where an Orion NPM server on a Windows 2008R2 box cannot connect to the mail server in our environment. The application logs show that it is indeed trying to connect but fails;...

How to force linux interface to work with specific network card

It's my first time expercience with multiples networks cards. I have two networks cards on my debian server. card 1: on on a public network, card 2 : on private network I have edit my /etc/network/...

Physical Firewall with seperation

I am not sure how to exactly describe this but I am looking for manufacturers and recommendations that could reduce my footprint in my current environment. I currently have 4 physical firewalls ...

Backup Client Computers using Windows Server or a NAS?

Not sure whether this is the right community to ask this question, so sorry if it's the wrong one!* Which option should (or is recommended) you use to make a backup of multiple computers (like 24-30 ...

ASA 8.4 port forwarding (static PAT) without objects

I personally think putting your PATs in the various objects is very ugly. I would like to do it without them. Every guide I see references doing the NAT in objects. I am trying to forward port 80 ...

Duplicate Ping Responses from single AD Domain Controller

Something I can't wrap my head around is happening with a DC on our network. I am a programmer by trade not a network engineer, but I am 99% sure this is not normal behavior. Anyway when I rebooted ...

Is there a way to create a share that does not require username/password when accessed all through the command line?

I know there's a way to do this from a GUI (Setting up an anonymous Windows Server 2008 network share?), but I am writing a script so I want to see if you can do it without the GUI. In other words, I ...

what is correct format for user name that is not part of domain

I have a windows 10 "Server Manager", and a VM with windows server 2012. I'm trying remote manage windows server, but server manager asks me username and password, neither local PC and PC both are not ...

Incomming connections have Docker host's IP address instead of the source's real IP when binding host's port to Docker container

I am running some services on some different Docker containers. As a simple example: docker run -it -p 123:123/udp ubuntu /bin/bash this -p 123:123/udp causes that all incomming connections to my ...

inconsistent speeds from different services. Mainly speedtest.net

I have had a few dedicated servers from online.net and they have all been great. But recently I have found issues with my connections on my new server. It is a Dedibox MD SSD 2015 Gen2 (Ubuntu 16.04)....

How do I use my .pem file from Amazon EC2 with mosh?

To login with ssh I do this: ssh -i ~/.ssh/kp1.pem ubuntu@ec2-xxxx.com I tried all this with mosh: mosh --ssh='ssh -i ~/.ssh/kp1.pem ubuntu@ec2-xxxx.com' mosh -i ~/.ssh/kp1.pem ubuntu@ec2-xxxx.com ...

How do you manage your server infos(IP/Name) [on hold]

In my company, on one know the exact server infos. An excel file is used to maintain all server lists(hostname/ip), but does not update on time. Someone may create several servers but forgot to add ...

Server not accessible on eth1 (additional network interface) CentOS 7 on AWS EC2

I have created a CentOS 7 instance on EC2, installed my required application-ware, assigned 1 Elastic IP to default network interface (eth0) and it is all accessible. Now I created another Network ...

How to DNS Fallback if host not resolvable

For a few docker containers I need a link between containers. This is done by docker-compose and works like a charm if (and that is sometimes the problem) the container is up. I am looking for a ...

Ubuntu Running KVM with 3 NICs Setup

I am currently trying to setup a KVM server with two OS (pfsense & Ubuntu Server) on an Ubuntu server with three NICs (enp2s0, enp1s0, & enp3s5). This is the concept I'm trying to do: http://...

Connection refused when trying to configure Chef Server 12 on RedHat 7

I am trying to set up a Chef Client on a VM to be configured to communicate with my Chef Server. The OS of both servers is RHEL 7.3. I run this command from a server I want to be a chef-client: ...

Do i need to start using SFP+ or is 1GBE sufficient from isp router to sonicwall?

We are in the process of upgrading our leased fibre line from 100mbps to 300mbps, and are currently using cat6 1GBe to connect from the ISP provided Cisco router to our Sonicwall NSA3600 (and ...

Manually specifying routing for an OpenVPN client [on hold]

I've set up an OpenVPN client on Raspbian which is working as expected and services on that machine are tunnelled through the VPN (on interface tun0). Unfortunately the default settings provided ...

What is this network device? [migrated]

Context: In a quest to convert my home from 100Mbps to gigabit, I encountered this device. Cables from the wall are coming in, Ethernet cable going out. As far as I understand, this device converts ...

Networking - Using public IPs for servers without NAT

So I am curious to know how this is done... Let's say your upstream provider has given you the following block of IPs 80.111.111.120/29 and for whatever reason you would like to use one of those IPs ...

Give a Windows 2008 VM Internet access but block Host LAN access?

Securing a guest VM to give it internet access, but block access to host LAN The above was a similar question asked for Linux but the following has specifics that are different. We need to have ...

How come I can ping between 2 different VLANS?

I've been trying to find an answer to this question and even asked a CCNA I worked with but it still is not making sense. Here's the scenario: I have an office that has multiple rows of computers ...

Should the Default Gateway be Firewall or DHCP/DNS server on Windows Domain Client PC

This is a bit of a theorteical question but it determines how I set up. On a Client computer within a Windows network should the "Default Gateway" be set to the Firewall or the DHCP server (which ...

Online.net ESXI 6 can not connect Ubuntu 16.04 VM to internet

I have setup a Failover IP with a MAC address and the Online.net docs say that adding in this interfaces config should be all that I need to do: auto ens160 iface ens160 inet static address ...

Assign public IP address to virtual machine in Ubuntu 16.04 [closed]

On Ubuntu 16.04 server (Host) I have installed VirtualBox 5.1. I want to assign additional public IP to Guest ( Ubuntu 16.04 ). From information so far i found i need to use bridged interface and ...

tcpdump filter does not work, why? [duplicate]

I have a machine which has a port connected to a monitor port on a switch. Thus, many packets from different sources and destinations are arriving at its interface. However, I cannot seem to filter ...

GRE tunnel TTL number

Here is the setting on server A: iface serverA_gre0 inet tunnel address 172.24.0.85 mode gre endpoint x.x.x.x dstaddr 172.24.0.86 netmask 255.255.255.252 ...

Send email from external server with cpanel/whm [closed]

I have recently switched my main cpanel/whm server to a new machine, and turns out all the IP's that were given are somewhat clean, but blocked with Outlook or some other wierd providers. Since that ...

Is it possible to find the distance between two networked devices? [closed]

Is it possible to find out how far away another device, within the same network, is from my computer? Are there any programs that can do this? I decided to use the formula distance = speed * time, ...

Is it possible to have a non-all-ones broadcast address?

We've been developing some scripts recently for auto-setting IP address details on our embedded devices. The method involved setting both the IP address details (e.g., 192.0.0.100/24 and the ...

QoS - MySQL Bandwidth Priority on CentOS / rhel

I have a highly loaded server and nginx is consuming all the available bandwidth, and i cannot connect to the mysql server (located on another machine) as i'm getting errors like Lost connection ...

Why do some mac-addresses repeat so often?

My application queries mac-addresses of client computers where it runs and stores them on the server. When I analysed the server DB, I found that some mac-addresses repeat 100-150 times. I.e. ...

OpenVPN for certain IPs, eth0 for everything else

Summary: I'd like to connect to my VPN and have access to certain servers, but for all other traffic I'd like to use my regular networking. I've setup an OpenVPN server on my VPS, my server.conf file ...

public ip to private ip translation in sonicwall.working with wan1 not working with wan2.please suggest

we are using soincwall tz210 firewall.We have two wan connections,from wan1(x0) we have created one policy with http.we can connect from out side networks by using wan1ip,but another wan2(x3) is not ...

How to convert local port number to ifIndex?

IF-MIB uses special ifIndex to control each interface. But LLDP-MIB uses local port numbers. Is there a way how to convert local port number to ifIndex? It is a trivial on several devices. For ...

Extracting Source => Destination rx / tx from procfs (/proc)

I know I can get rx and tx bytes for each NIC from /proc/..., but I'm looking to get rx and tx info for each source => destination pair -- basically traffic info for each network connection. In /proc/...

How to connect to a BGP network? [closed]

A service provider we're working with delivers us data via two(for resiliency) 1Gbps cross connects. He's located in a datacenter nearby the datacenter where our server is located. We don't have a ...

Is there a load balancer that will terminate a GRE tunnel?

I have a network in which several site routers send portions of their traffic to an inspection device via GRE tunnel. I am beginning to exceed the capacity of the inspection device. I could always ...

Shorewall reporting martians

Running Shorewall v5.0.14.1 on Fedora Server 4.8.15-200.fc24.x86_64 configured with two interfaces (br0 and team0). Interface br0 connects to Internet while the team0 interface connects wireless ...

Which Ports need to be accessible on a Domain Controller for Clients to logon? continued

With reference to one of the questions asked "Which Ports need to be accessible on a Domain Controller for Clients to logon?" I have a aligned issue being faced. Please see the following ports which ...

Stand-alone Cisco switch in BladeCenter is un-pingable

After un-stacking a Cisco switch in my IBM blade center I can no longer ping the management IP I had configured on my management VLAN. The only item I see that changed is that the Bladecenter AMM ...

Private connection between Windows Server

I have two Windows Server 2012 R2, they have 2 NICs each one! One for Public netw. and another for Private. I need to daily transfer data from Server A to Server B and would like to do it via the ...

Monitoring unauthorised access using opennms/observer

I have recently started playing around with network managment tools (opennms and observer analyzer). I wanted to find out how would a network manager find out about unauthorised activity on the ...

Public IP on vmware esxi ( Softlayer )

We have dedicated private ESXi server in Softlayer.The server on start had one private IP assigned to vmnic0 vmotion and 4 interfaces total. Interfaces are teamed ( vmnic0 and vmin2 - privat / ...

Cluster nodes cannot ping the external networks (like google.com)

I have a cluster with 1 login node and 100 computation nodes. I can ping the external networks including google.com from the login node. However, I cannot from the computation nodes. The computation ...
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