Questions tagged [tcpip]

TCP and IP are two important protocols used in networking today. Due to their importance, the Internet Protocol Suite is also commonly known as "TCP/IP"

Filter by
Sorted by
Tagged with
0
votes
0answers
10 views

When the results stored based on ipv6 flow label be used?

I have gathered some information on IPv6 flow label. It is used to identify a specific flow from one source to one destination and from the first new flow labelled packet received, the ipv6 header, ...
0
votes
1answer
41 views

How to enable ECN marking in IP header in Linux

Is the ECN marking in the IP header is performed by default in Ubuntu (4.15.x kernel) or should the kernel be recompiled with a special option? I configured a RED ingress queue at an Ubuntu machine, ...
-1
votes
1answer
49 views

SSH connection not established, but standard TCP/IP connection works

I'm working on a custom yocto Linux for a Raspberry PI 3 and try to get the WIFI connection working with SSH. However when trying to connect from my PC (Ubuntu 19.10, SSH OpenSSH_8.0p1 Ubuntu-6build1, ...
0
votes
1answer
36 views

What do i need to take to connect an openvpn server to a local network?

I'm setting up an office vpn so people can work from home, by rdp'ing their office machines by connecting to a vpn server which is based on the office lan. It wont be as simple as creating a vpn ...
0
votes
1answer
36 views

Is it actually possible to send some data to remote destination over tcp/ip without any socket?

I am studying socket concept. As far as I learned socket is like electrical socket that is created in both end of communicating devices (or processes). Socket can keep itself alive forever to listen ...
0
votes
0answers
23 views

TCP state transitions during active close vs. tcp_fin_timeout

Background The regular state traversal sequence during an active close of a TCP connection is as follows: ESTABLISHED (appl: close, send FIN) FIN_WAIT_1 (recv: ACK, send <nothing>) ...
0
votes
1answer
48 views

Ping a host in other network

I have a Virtual Machine One in inner network 192.168.1.0 with ip address 192.168.1.1 and Machine Two in inner network 192.168.2.0 with ip 192.168.2.2. Both have enp0s3 interface. How could I ping 192....
0
votes
0answers
530 views

TCP/IP: no SYN/ACK response from dedicated 'OVH kimsufi' server after client sending SYN for port 873 (rsyncd)

From the client debian 9 (IP 2.2.2.2 for example) : # iptables -L [...] Chain OUTPUT (policy ACCEPT) target prot opt source destination test rsync or telnet doesn't access remote ...
0
votes
1answer
44 views

TPC lost segment

I'm investigating an issue where the application (Java based) didn't receive the whole message which was split on two TCP segments. I have a trace that proves that both segments was sent to the server....
0
votes
1answer
579 views

How to add more than 2 DNS servers in a domain

I have 3 DNS servers in my environment that I'd like to show up on my end users machines for backup. 2 onsite and 1 in Azure. I have a site 2 site VPN connection between HQ and Azure. When I go to ...
0
votes
0answers
15 views

Control source IP used by ASP.Net application pool or site when connecting to remote services

Using Windows Server 2016 with multiple IP addresses configured on the same NIC. I have an ASP.Net web application that connects (using built-in .Net classes) to an external web service. I would ...
0
votes
0answers
16 views

What are *all* the causes for `Failed connect to …; Connection refused` error message? [duplicate]

At times during the night,(1) without any discernible pattern connections(2) to GitHub would fail with: fatal: unable to access 'https://github.com/xxxxx/cmake/': Failed connect to github.com:...
0
votes
1answer
1k views

Windows Server 2012 R2 SYN Flood Attack?

I have a Windows Server 2012 R2 IIS web server, running on VMWare esxi 5.5, hosting multiple websites with different IP addresses. This server recently has been refusing connections randomly across ...
0
votes
1answer
532 views

How do I bind to UDP port 53 in GCE (Container-Optimized OS)?

Is there any way to free up UDP port 53 on my GCE instance so that I can bind to it? I'm running a container on GCE that needs to listen on UDP port 53, as it's listening for DNS connections. However,...
1
vote
0answers
84 views

DNS resolving timeout

I have a DNS in Linux Centos 7, and when integrating with Windows Server 2012 R2 it only solves in an inverse way, that is, with its IP address, when I try to resolve directly the server, it takes a ...
1
vote
0answers
84 views

Unable to connect to my winsock server using external IP

When I try to connect to my simple winsock server using my localhost/LAN IP, the connection is established with no problems. However, if I attempt to do so using my external IP, I keep getting ...
6
votes
0answers
576 views

Is there a TCP Maximum Segment Size (MSS) Minimum?

I have there a OpenVPN VPN network connection, where the MSS size 60 gets send out for some reason (don't know why yet). EDIT: Reason: OpenVPN mssfix was mistakenly set to 1 36 92.064383 10.102.0....
2
votes
1answer
427 views

Tuning network interface for TCP over TCP in Linux

I'm porting a legacy embedded application to Linux. This application communicates with a remote server over a TCP connection using a proprietary protocol. In addition to the application specific ...
0
votes
0answers
3k views

Why TCP Out-Of-Order packet is seen after SYN?

I am trying to troubleshoot a performance issue between a client and a file server. When I look at the capture from the client, I see a weird behavior. I am trying to understand this weird behavior. ...
3
votes
1answer
2k views

AWS flagged my subnet as invalid although it looks to be within the VPC CIDR block

My VPC CIDR block is 10.0.0.0/16 As I understand it, this should support 256 (effectively 254) subnets with 65534 hosts per subnet. When I tried to create one subnet 10.8.0.0/24 and associate it with ...
0
votes
0answers
500 views

How to debug IIS 8.5 TCP resets?

I have a Win 2012 R2 / IIS 8.5 server that has been running a handful of public-facing production websites for 2 years. Today, for about 6 hours, it started randomly dropping port 80 requests (but ...
0
votes
0answers
48 views

Connection timout between two IP troubleshooting

I have a client with a webserver and a VPS server with a webserver and a mailserver. These machines have to exchange data via REST API but I have a problem, they are not reachable each other over HTTP ...
4
votes
0answers
777 views

What is the difference between net.core.netdev_max_backlog and net.ipv4.tcp_max_syn_backlog

Several docs on the net describe these options as following: net.core.netdev_max_backlog: Maximum number of packets, queued on the INPUT side, when the interface receives packets faster than ...
1
vote
1answer
34 views

Why does LAN stops working if switch is connected to two upfeeds?is [closed]

If I connect my switch to two upstream feeds from my ISP, my internal LAN stops functioning (see illustration below). What is it in the TCP/IP protocol that is disrupted to cause the above? ...
-1
votes
2answers
64 views

Is there URL filter like protocol in TCP/IP stack?

I find many type routers have their self-existent URL filter settings. Tenda: Nexxt: So, is there a URL filter protocol in TCP/IP stack? and if is, is there any software for controlling every ...
2
votes
1answer
1k views

How can iperf reporting packet loss in udp

Iperf is the well known tool to calculate throughput. When i tried udp throughput using iperf on my linuxpc, It reported that 10% of packet loss. In UDP protocol, data gram did not receice any ...
0
votes
1answer
43 views

Windows Server 2011 - System opening ominous TCP connections

Where I work we have a Windows Server 2011 Small Business edition, and recently our Symantec software started reporting "blocked intrusion attempts" from port 80. Our routers do not forward any port ...
2
votes
1answer
386 views

Sysinternals Sysmon: How to log an unsuccessful TCP/IP connection attempt

I would like to use Sysmon to log an unsuccessful TCP/IP connection attempt. For example, with the following configuration: <NetworkConnect onmatch="include"> <DestinationPort condition="...
2
votes
1answer
105 views

why are there are so many svchost established connections to Isilon?

Our client has a Isilon (used only for smb) with few nodes attached to it. When I run TCPView I don't understand why svchost service established the connection and why there're so many of them: And ...
0
votes
1answer
22 views

Which parameters and setting affect network throughput when connecting two machines together without a switch?

I have a situation where I need best possible throughput (TCP/IP sockets & SMB3) between two Windows Server 2016 connect with a 1m patch cable. I have to use existing hardware. When you connect ...
-1
votes
1answer
35 views

Weird behavior of VPS host

Hi I noticed strange behavior on my VPS host I launch nmap on my laptop and scan VPS host nmap screenshot Listed netstat on VPS server netstat screenshot Tried to connect to some port connection ...
0
votes
3answers
575 views

diffrence between csma/cd and tcp/ip

I finished my middle school IT & Networking education about 2 years ago. Now I recently got a job and started to refresh my knowledge. I've been searching the internet first of course but I still ...
7
votes
4answers
2k views

Windows 7 Client flooding network with DHCP requests. Not setting IP

I have a small network, with 15 workstations, SAMBA AD, and a bunch of Virtualized linux servers. All the workstations, and servers are on the same subnet. All workstations are running Windows 7 Pro ...
1
vote
1answer
985 views

TCP Initial Handshake Incomplete (ACK Missing)

I am irritated about the following scenario: I am running a MVC application on an IIS 10 Webserver. While calling the URI, it takes about 10 seconds until the application starts to get called (IDLE ...
0
votes
1answer
1k views

Why does TCP request packet contain ACK flag? [closed]

I am very new at low level of TCP and I am tryingtcpdump with simple socket server and client program. The server and client follow the two steps. Server and client make a connection. Client sends ...
5
votes
2answers
6k views

Linux: tracking the source of netstat -s “failed connection attempts”

I have several servers, where the failed connection attempts metric returned by netstat -s (from /proc/net/snmp) grows by roughly one per second, and I'd like to diagnose the source of these. By ...
0
votes
1answer
79 views

can only ssh unidirectional

I have two centos 7.2 server. One machine ip is 10.104.196.18, another machine is 10.240.197.21. I can successfully ssh from 10.104.196.18 to 10.240.197.21. But failed to ssh into 10.240.196.18 from ...
0
votes
1answer
413 views

ARP responses from host with several interfaces

I have a (experimental) setup where a host myhost.mydomain has three network interfaces all connected to the same VLAN as its default gateway mygateway.mydonain. The setup looks as follows: interface ...
0
votes
1answer
309 views

How do I get Kubernetes to work without the “connection over port 8080” error?

I installed Kubernetes in RHEL 7.x. I expect kubectl commands to work without errors. Port 8080 is not being blocked from my client workstation to the RedHat server with Kubernetes. I tried several ...
0
votes
0answers
194 views

OpenVPN network as part of server subnet

I have a server connected to network 192.168.200.0/24 it is our local network office's and 172.20.0.0/16 it is VPN network shared in office. And I have install OpenVPN server on the same server in ...
1
vote
2answers
3k views

MaxUserPort setting seems to be ignored

One of my .NET applications is getting the following exception when firing ~300 HTTP requests in a span of about 1 minute: System.Net.WebException: Unable to connect to the remote server ---> ...
0
votes
0answers
350 views

Is direct hosting SMB 3.x over TCP standard or optional these days, if optional how do I make my computer use it?

I just came across this page ("Direct hosting of SMB over TCP/IP"). It's quite old, so I can't be sure if it's the standard these days. It refers to disabling NetBIOS over TCP and disabling WINS, ...
0
votes
2answers
1k views

Windows Server 2012 R2 can't establish outgoing TCP connections

I've got a very weird error in a server. It is a Windows Server 2012 R2 Standard Domain Controller (primary) running in VMware ESXi 6.0 U2. It has DNS, DHCP and some file shares. The error is that it ...
0
votes
1answer
245 views

Slow UNC paths on virtual Windows Server 2008R2

We have a virtualized Windows Server 2008R2 running on a host Windows Server 2012R2. The 08R2 server is also running SQL Server 2008R2 SP3 (Version 10.5) and IIS 7.5. Lately we've had intermittent ...
0
votes
2answers
1k views

How do I allow communication between two Azure virtual networks with their own VPN gateways

I need some help (or maybe a better angle of attack) connecting a few external users to our Azure tenancy. NOTE: All resources mentioned below are in the same Azure Subscription, the same Azure ...
-2
votes
2answers
158 views

What happens to a tcp packet when two access points for the Same SSID are on the same channel

Working on a C# Tcp server that is communicting with an embedded IOT device and I was having serious communication problems. Packets getting lost and or delayed. Not receiving ACK...ect It turns out ...
0
votes
2answers
747 views

Checking open rdp ports from script

I need to find out what server ports are listening on port 3389. I have to check 2500 servers, some in different vlans, to make sure remote desktop is enabled. Can netstat be used to check this and ...
-1
votes
2answers
815 views

OVH : SSH Connections Timout after multiple connections

So i have making a control panel of sorts with php on my webserver that is able to send commands to my dedicated server (remote server) via ssh2. This works fine, however i have noticed that after a ...
0
votes
2answers
128 views

How to understand the “A subnet Example”?

In A Subnet Example of TCP/IP Illustrated, Vol. 1: The Protocols , there is a Figure and a table: and under the thick Line in dash rectangle, there is Ethernet, subnet 140.252.13.32, and in table, ...
0
votes
1answer
139 views

route loop while ping one server with 3 NIC in 3 separate networks

I have this server used for testing some network parameters. It has 3 separate network cards, each with the below IP configuration: 192.168.10.150/30 gw 10.149 192.168.152.146/30 gw 152.145 192.168....

1
2 3 4 5
9