TCP/IP

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Transmission Control Protocol/Internet Protocol (TCP/IP) is the set of networking protocols that define end-to-end connectivity specifying how data should be packeted, addressed, transmitted, routed and received at the destination. This functionality is organized into four abstraction layers which are used to sort all related protocols according to the scope of networking involved.

We are going to be moving a server to a new Location and the IP address on the server needs to change.

What would be the steps to take on the server when you have to change it to another IP address.

I found these steps online. Can you let me know it this is accurate?


[b]To perform this procedure, you must be a member of the Domain Admins group in the domain of the domain controller whose IP address you are changing.

To change the static IP address of a domain controller
Log on locally (also known as interactively) to the system console of the domain controller whose IP address you want to change. If you are not able to log on to the domain controller by using the domain, you may have to start the domain controller in Directory Services Restore Mode (DSRM). For more information, see Restart the domain controller in Directory Services Restore Mode locally (https://lazyadminblog.wordpress.com/2015/04/11/restart-the-domain-controller-in-directory-services-restore-mode-locally/).
On the desktop, right-click My Network Places, and then click Properties.

In theNetwork Connections dialog box, right-click Local Area Connection, and then click Properties.
In theLocal Area Connection Properties dialog box, double-click Internet Protocol (TCP/IP).
In theInternet Protocol (TCP/IP) Properties dialog box, in the IP address box, type the new address.
In theSubnet mask box, type the subnet mask.
In theDefault gateway box, type the default gateway.
In thePreferred
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I have SysAdmin role/rights on a SQL Server 2016 server.   The server is physically located several states away.  I can Remote Desktop into the actual server box, start SSMS, and do whatever actions I want (including edit Job Steps).

When I start SSMS from my laptop and connect to the server I can do whatever actions I want EXCEPT edit and save SSIS Jobs.  The server has TCP/IP turned on and using port 1433.  
When I go into a Job's Properties, go to "Steps" page, select a Step, and then click "Edit" to edit a job step I would get the error:

TITLE: SSIS Execution Properties
------------------------------

Connection Timeout Expired.  The timeout period elapsed while attempting to consume the pre-login handshake acknowledgement.  This could be because the pre-login handshake failed or the server was unable to respond back in time.  The duration spent while attempting to connect to this server was - [Pre-Login] initialization=19958; handshake=14045;  (Microsoft SQL Server, Error: -2)

------------------------------
ADDITIONAL INFORMATION:

The wait operation timed out
------------------------------



After fiddling with a bunch of permissions, I now get this error:

TITLE: SSIS Execution Properties
------------------------------

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to…
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My private IP addressing is in the 10.10.10.x network, 255.255.255.0 subnet mask, 10.10.10.1 is the default gateway. Now on some computers, I am getting a subnet mask of 255.255.255.128. I couldn’t figure out why?
Can someone help me with this?

I actually replaced the switch, thinking that some ports on the switch were bad, but I keep getting the same issues.

Thanks!
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just a general question
when I try to ping my router from a local computer which is connected with lan cable- ping time is ms<1, ttl is 255
when I ping my server in same lan:
ping time is <1, but ttl is 128

why there is vary in ttl when I ping my sever and router from same local computer . anything I need to worry ??
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I'm using C++,  WxWdigets and Ubuntu and sometimes my application needs to send TCP packets to a TCP server.
The packets are in this format:
std::array<uint8_t, 8> command1;

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I'm using a non-blocking TCP client method from boost asio and it works pretty well.
The problem is that I need to change the content of command1 since I need to send 32 different values depending on users actions.

At the moment, I connect to the server by using start_connection() function which connects to the server and execute the function start_write(int scelta) which sends the command1 over the net.

I would like to call the start_connection() function by passing the value of command1 in order to send it with start_write() function.
Is there any solution to do this?
Or, is there a smarter and faster solution to acquire what I need?

#include <boost/asio/buffer.hpp>
#include <boost/asio/io_context.hpp>
#include <boost/asio/ip/tcp.hpp>
#include <boost/asio/read_until.hpp>
#include <boost/asio/steady_timer.hpp>
#include <boost/asio/write.hpp>
#include <boost/bind.hpp>
#include <iostream>
#include <string>

using boost::asio::steady_timer;
using boost::asio::ip::tcp;

std::array<uint8_t, 8> command1;

class client
{
public:
  client(boost::asio::io_context& io_context)
    : stopped_(false),
      socket_(io_context),
      deadline_(io_context),
      heartbeat_timer_(io_context)
  {
  }

 
  void start(tcp::resolver::results_type

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We have an AIX unix server we need to connect to and then run two commands using C# or something in SSIS. How can we do this? Ultimately we are working to automate what is currently a manual task for us.

cd /strbus/fw
sh job/edid2c
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ISP uses router in front of my firewall and They use dedicated public IP block  (WAN and GW) for the connectivity.

My firewall WAN IP and other external IPs are in completely different range.

With traceroute , Router's LAN IP 10.xxx.xx.1 is getting listed as the first hop and next is ISP GW IP. The public IP assigned in router (WAN) is not getting listed.

Is this common situation with traceroute or what is the theory behind this ?
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I have a rsh command to connect to a UNIX box from a Windows XP box via TCP/IP. I replaced the rsh with PLINK after the Windows box migrated to Windows 10. Below is the example of the command. I still used the same PORT ID but got connection refused error. Then I added the parameter "-P xxx" but still failed.

rsh [unixHost] -l [hostlogin] mv [file_1] [file_2] ===> PLINK [unixHost] -l [hostlogin] mv [file_1] [file_2]

Questions:
1. For this kind of conversion, can we use the same TCP/IP PORT ID?
2. It seems that PLINK has more security restrictions than rsh. Need help on how to solve this problem.

Thanks for the help.
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Trying to figure out a better way to manage IP addresses.

In a typical scenario, let's say a DHCP server is given a scope that is a subset of usable IPs. For example, 192.168.20.50 - 250. IPs less than 50 are not in the scope because those numbers will be manually/statically assigned to servers and networking equipment. Now, fast-forward a few years and you wish you had more non-DHCP addresses because you have new devices that you want to assign static IPs to.

So, spin up a new VM, let DHCP assign it an IP address right smack in the middle of your DHCP scope; then right-click on that record in DHCP and convert it to a reservation.
That I suppose would be sufficient, but there's something about leaving the server's network adapter set to DHCP forever so my preference/tendency is to remote into the server and change it to manual, and then manually type in the IP address that I just reserved. But now that IP address is no longer a reservation. It's static! So in the DHCP server I change the IP address to an exclusion rather than a reservation.

Seems like the proper(ish) thing to do, but now I have all of these holes in my DHCP scope and the exclusions you set on the DHCP server are nothing more than a list of IP addresses with no clue as to what they were used for. I like the 'reservation' method because it will literally tell you the name of the computer you reserved it for, its MAC address and it falls nicely into place when you view the list of IPs. But as I …
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Hi Experts!

Now after battling with the “POST” method under http to send data for tax purposes assessments, finally it is dropped, we are given another option which I thought was more straight forward. However, I still need some guidance on how to use the TCP/IP port system in Ms Access VBA code
Below are the port system sample:
Module IP: 192.168.88.577
Port: 10009860Y
Baud Rate: 96089
Data Bits: 8
Parity: None 
Stop bits: 1 

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How do declare the above stuff into the VBA code below so that the converted Json data string can be sent to Port: 10009860Y????????

Private Sub CmdSales_Click()
  
'  Const SQL_SELECT As String = "SELECT * FROM Qry3;"
  
  Dim coll As VBA.Collection
  Dim dict As Scripting.Dictionary
  Dim db As DAO.Database
  Dim rs As DAO.Recordset
  Dim fld As DAO.Field
  Dim qdf As DAO.QueryDef
  Dim prm As DAO.Parameter
  
  Set db = CurrentDb
  Set qdf = db.QueryDefs("Qry4")
For Each prm In qdf.Parameters
    prm = Eval(prm.Name)
Next prm
Set rs = qdf.OpenRecordset()

Set qdf = Nothing
  Set coll = New VBA.Collection
'  Set db = CurrentDb
'  Set rs = db.OpenRecordset(SQL_SELECT, dbOpenSnapshot)
  If Not rs.BOF And Not rs.EOF Then
    Do While Not rs.EOF
      Set dict = New Scripting.Dictionary
      For Each fld In rs.Fields
        dict.Add fld.Name, rs.Fields(fld.Name).Value
      Next fld

      coll.Add dict
      rs.MoveNext
    Loop
  End If

  rs.Close
  Set fld = Nothing
  Set rs = Nothing
  Set db = Nothing
  Set dict = 

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Hi, I have Windows Fail Over  Cluster configured as below in VMware vSAN environment:

Production Network: 192.168.50.0/24

Cluster Heartbeat Newark: 10.1.1.0/24 (Communication only between two cluster nodes, no gateway, DNS specified, only IP and mask)

vSAN iSCSI shared storage network: 172.31.10.0/24  (Communication only between vSAN and Windows iSCSI initiator, no gateway, DNS specified, only IP and mask)

Windows cluster is configured, and the cluster test is passing. I can restart the servers and cluster switching is working fine.

The problem is, that we have an application, which is supposed to bind to the Production network (usually it does it automatically), where it can communicate with other servers in the network, however, it always binds to Heartbeat network. How to get the nic priority level sorted. I followed the steps in the below link, but no luck.

https://www.mssqltips.com/sqlservertip/4928/configure-network-binding-order-for-a-windows-server-2016-failover-cluster/

We need urgent help.
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I’m not sure why but I cannot seem to get Secure Print to work for a Canon iR-ADV C3530 III network printer. We have the badge authentication part working (there’s a card reader that in top of printer that reads badge mapped to an AD fax attribute for identification) but it’s useless this far since there are no way to secure print and require authentication at printer.  
When I do straight prob tit works. But if I choose Secure Print in output method from printing it goes through a pin code prompt and says it prints but nothing gets to the printer. Anyone know how this typically works and is setup? I’ve tried GPO deploy to my machine, doing direct TCP/IP connection as well.
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My application consists of  GUI application, an  application which resides on controller  and the server application. I am developing my application with C++ for the Poco libraries. The controller should communicate with the GUI and the server through the TCP /IP protocol. So My question here is whether I need to setup my GUI as server? If some one can forward me the sample of TCPServer created with Poco libraries which listens to specific ip adress and port.
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HI, we have a customer that uses unmanaged switches and has used all of thir 254 IP address on the local network.
What is the best way to achieve more local IP addresses on the LAN
Thanks
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I have SCO Unix 5.0.5
I am trying to Add LAN Adapter
Using netconfig program
Add Hardware Lan Adapter finds the Intel/100b on the motherboard.
Add Protocol finds no Protocols to add

tcp, ifconfig, and other basic programs for working with TCP/IP cannot be found

Does SCO 5.0.5 require a separate installation package and maybe a separate license?

Thanks
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Hello i am trying to do an asynch server tcp in c# and i get this error and can not resolve it please

Request for the permission of type 'System.Net.DnsPermission, System, Version=4.0.0.0,

thanks for your help

my code :
 public static void StartListening()
        {
        Console.WriteLine("started point");
            // Establish the local endpoint for the socket.  
            // The DNS name of the computer  
            // running the listener is "host.contoso.com".  
			
	    string host = Dns.GetHostName();
	    IPHostEntry ipHostInfo = Dns.GetHostEntry(host);
            IPAddress ipAddress = ipHostInfo.AddressList[0];
            IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);

            // Create a TCP/IP socket.  
            Socket listener = new Socket(ipAddress.AddressFamily,
                SocketType.Stream, ProtocolType.Tcp);

            // Bind the socket to the local endpoint and listen for incoming connections.  
            try
            {
                listener.Bind(localEndPoint);
                listener.Listen(100);

                while (true)
                {
                    // Set the event to nonsignaled state.  
                    allDone.Reset();

                    // Start an asynchronous socket to listen for connections.  
                    Console.WriteLine("Waiting for a connection...");
                    listener.BeginAccept(
                        new AsyncCallback(AcceptCallback),
     

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I had this question after viewing Getting postfix to send out a specific interface.

I'm running Debian Linux with postfix installed, the server is also an apache web server .. there are a total of 19 interfaces not including the loopback ..

The issue is that our hostname www.example.com resolves to a specific IP address and postfix sends from a different address.. this causes some servers to reject our mail since the forward doesn't match the reverse.

In my main.cf the two relevant lines are:

inet_interfaces = all
#smtp_bind_address=64.XX.XX.130

The issue is that when I set smtp_bind_address, outbound mail no longer works .. I get the following error:

postfix/smtp[16332]: 9C82836712: to=<xxxx@gmail.com>, relay=127.0.0.1[127.0.0.1]:10025, delay=0.13, delays=0.12/0/0/0, dsn=4.4.2, status=deferred (lost connection with 127.0.0.1[127.0.0.1] while receiving the initial server greeting)

The moment I disable that line and restart postfix, mail starts flowing again ..  the interesting thing to note is that postfix appears to be binding to the last interface, I could swap those but I'm hesitant to do that..

What is the solution? I've searched but can't find the answer
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2 Recently installed HP elitebook laptops with windows 10.
Client has windows server 2012 which is the DNS server in their domain.
They have a Meraki access point, and when one of the laptops leaves the wifi network, it doesn't work on other wifi networks.
Upon investigation, the wireless adapter's properties had the IP address of their domain server in the TCP/IP properties under: use the following DNS server addresses:  instead of obtain automatically, as it should be.  We removed it and changed to obtain automatically, but every time she's in that network, it changes back.  
The other laptop does not have this issue.
I've never encountered this before, and not sure what is changing it or how to stop that behavior.
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I have OpnSense (Another version of Pf Sense) Firewall installed. I can not get out to the Internet on my second, 3th, 4th LAN ports.
I have an OpnSense Firewall PC box I made which has the following inside…
OpnSense 18 (latest version) https://opnsense.org/about/about-opnsense/ 
-G.SKILL Ripjaws V Series 16GB (2 x 8GB) 288-Pin DDR4 SDRAM DDR4 2400 (PC4 19200) Desktop Memory Model F4-2400C15D-16GVB
-King Spec SATA III 3.0 2.5" 60GB MLC Digital SSD Solid State Drive for PC B5Y1
-AMD Athlon 200GE 2-Core, 4-Thread, 3.2 GHz Base, Socket AM4 35W YD200GC6FBBOX Desktop Processor
-ASRock A320M-HDV AM4 AMD A320 SATA 6Gb/s USB 3.0 HDMI Micro ATX AMD Motherboard
-80 plus bronze certified power supply 380Watt
-Dell Intel PRO/1000 VT Quad-Port Gigabit Ethernet Card Standard Profile YT674
-IOCrest 4 Port Gigabit Ethernet PCI-e x1 Network Interface Card SI-PEX24042
This is inside a 4U server Case, inside an APC 48U Server Rack


 
My goals are the following...

-      I want to one 4 Port NIC using different IP Addresses such as
10.10.10.1 --- Web server Network
2.2.2.1---- Entertainment Network
90.90.90.1---- Work Network
30.30.30.1 --- Web server Network
I already setup these networks inside my box but I am willing to START from the beginning if you need me too.

-      I want the networks not to be able to talk to each other.
-      I have 5 block of Public static IPs which I want to use.
-      104.XX.xx.1--- This is assigned to the OpnSense itself
-      
-      104.xx.xx.1 talks to …
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We have a system that is meant to send out data and messages to an external system (via 443/tcp 80/tcp). This extract system was working perfectly well when our internal system was hosted on Server 2008 R2. We have recently upgraded to 2012R2 and the extract is unable to send outbound data except we have an active browser session by launching the browser and visiting an external website (any website at all as long as it is on the internet). Once the Browser session is closed, the outbound transfer of data becomes impossible.

Thank you
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Hi All,

I recently upgraded our Cisco ASA 5545 to version 9.9(2)36.  Since the upgrade we are not able to transfer files to/from our Azure tenants via the site to site vpn we have setup.  Here is an example:  

Local Server: 10.1.1.151
Azure server: 10.211.20.100

We can ping both ways fine, but file trans are failing.  It just hangs when I try a transfer.  For the monitoring I am seeing TCP Reset-I from inside.  Could this be the reason the file transfers are failing?  If so, anybody have any idea how to remedy that reset??

Jan 08 2019      08:25:33      302014      10.211.20.100      445      10.1.1.151      51178      Teardown TCP connection 38499637 for outside:10.211.20.100/445 to inside:10.1.1.151/51178 duration 0:05:53 bytes 5384 TCP Reset-I from inside

Thanks in advance.
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Hello,

If I am running a tcp ping tool on a virtual windows server that is hosting my website also, would it be possible to use the tcp ping tool to ping the visitor of my website to record the latency/round trip time without the stateful firewall blocking it?

The issues I came up with would be that all/most home-based firewalls are stateful firewalls, tcp communication can use only one IP and one port(if I am correct?) per application (website in this scenario). So I would have to have the tcp ping application listen in on the port using another IP, or open a new port (and IP) to communicate with the same website user. So my second question would be: would the stateful firewall block this communication since it is from a different port and/or IP even though it's on the same web server?
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VBOXerr1.txtSSH connection refused when running SSH (putty) from my WINDOWS PC a  an ORACLE LINUX running on the same PC on Oracle Virtual BOX.

PUTTY displays the error:
PUTTY Network  error:  Connection refused  on 192.168.56.1

Sure, something is wrong. Could you help?

RegardsVBOXerr1.txt


I already attached a log from the Windows8  machine (ipconfig ).
What I am ryng to do is connect from Windows using putty (SSH) to the VM Linux running on the same machine .
Someone can give any advice?

See below the ifconfig of the VM Linux machine:

root@ServidorLinux7 ~]# ifconfig
enp0s3: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.0.2.15  netmask 255.255.255.0  broadcast 10.0.2.255
        inet6 fe80::52d0:9ddb:1f83:48f2  prefixlen 64  scopeid 0x20<link>
        ether 08:00:27:5d:46:25  txqueuelen 1000  (Ethernet)
        RX packets 6787  bytes 4818007 (4.5 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4517  bytes 617833 (603.3 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 0  (Local Loopback)
        RX packets 46  bytes 7314 (7.1 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 46  bytes 7314 (7.1 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  …
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Something is going on with our network and I don't know where the issue is.  Many downloads (but not all) consistently halt with a [RST] but always the same ones, like PowerISO download.  Windows update fails with a Network Error on all PCs.  This is happening on both Windows and Linux.  Attached is a wireshark capture (it opens in Wireshark is you have it installed and double click it) and the jpeg screen shot.

We have COX as the internet provider but I don't know what is causing the problem.  

Can someone please take a look?  Thank you.

Wireshark Screen capture of [RST] download failed.RST_during_Windows_Update2.cap
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I a running an HTTP server on Ubutnu which handles GET requests.  I want to send the payloads to the client in as large of packets as possible.  However, when I look at tcpdump output, I see the payload being broken up into many small packets, typically between 1448 and ~6000 bytes.  I have tried turning off tcp_window_scaling on both client and server, but that did not work.  What settings should be adjusted on server and client to get as large of packets as possible?

Server: Ubuntu SMP Thu Aug 16 16:21:21 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
Client: Ubuntu SMP Mon Sep 24 16:19:09 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

tcpdump:

13:03:31.227151 IP serverIP.port > clientIP.port: Flags [.], seq 1452077:1453525, ack 4279, win 60032, options [nop,nop,TS val 43798667 ecr 1911733405], length 1448
13:03:31.227154 IP clientIP.port > serverIP.port: Flags [.], ack 1453525, win 65529, options [nop,nop,TS val 1911733424 ecr 43798667], length 0
13:03:31.227161 IP serverIP.port > clientIP.port: Flags [.], seq 1453525:1454973, ack 4279, win 60032, options [nop,nop,TS val 43798667 ecr 1911733405], length 2896
13:03:31.227162 IP clientIP.port > serverIP.port: Flags [.], ack 1454973, win 65529, options [nop,nop,TS val 1911733424 ecr 43798667], length 0
13:03:31.227184 IP serverIP.port > clientIP.port: Flags [.], seq 1454973:1456421, ack 4279, win 60032, options [nop,nop,TS val 43798667 ecr 1911733405], length 1448
13:03:31.227186 IP clientIP.port > serverIP.port: Flags [.], …
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TCP/IP

11K

Solutions

17K

Contributors

Transmission Control Protocol/Internet Protocol (TCP/IP) is the set of networking protocols that define end-to-end connectivity specifying how data should be packeted, addressed, transmitted, routed and received at the destination. This functionality is organized into four abstraction layers which are used to sort all related protocols according to the scope of networking involved.