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.

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EDUCATIONAL QUESTION: I need to gain some knowledge our of necessity. Here is the situation. I do NOT know my way around things such as: 1. What the function of DHCP is; 2. Why port forwarding is necessary in some instances; 3. How to configure the ip addresses of my surveillance cameras; 4. How to start anew with my NVR and surveillance system.

I did not want to take the time to educate myself on these items since I would seldom have need for this knowledge. However, since I just got a new fiber isp and virtually nothing operates properly on the surveillance system I think that I must gain the knowledge necessary to do this myself. The company I purchased 70% of the system from will assist me somewhat but refuses to assist in any way at all for the cameras that I did not purchase from them. There are many free utility programs available that I have  installed, however I need the knowledge to determine what to do with them. I think you get the picture. What my question is: Can any Expert advise me of an online course that will teach me what I need to know to understand this area of technology that will not take me overboard? I will not be doing this for a living. I just need to know what is needed to enable me to restore my system to default and start anew and KNOW what I am doing. I wish I didn't have to take the time needed to learn this, but I cannot locate a person that can guide me through all that is necessary to get things up and operating again. I would feel …
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C++ 11 Fundamentals
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C++ 11 Fundamentals

This course will introduce you to C++ 11 and teach you about syntax fundamentals.

Meaning of TTL in PING Reply

I have pingged 2 devices that have the same number of Hops away.
One shows TTL:124
the other shows TTL:250

I wonder how is the TTL calculated in this case .

Thank you
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Host Address Range in IP Subnetting

I have this IP address: 10.65.211.46 subnet mask 255.255.254.0

how can I calculate The host address range to come up with first host:10.65.210.1  and the last host: 10.65.211.254

Thank you
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I HAVE A HAEMTALOGY ANALYZER WITH RJ45 PORT. I NEED TO RECEIVE DATA FROM THAT MACHINE TO MY VB.NET PROGRAM. KINDLY SHARE THE CODE FOR THE SAME SO THAT I CAN GET THE DATA AND RESTRUCTURE THE SAME AS PER MY REQUIREMENT.
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I am having trouble using the Mitov Openwire VCL components TVLIPCamera.
I am writing a Windows 32 C++ application using Embarcadero XE10.2 to stream video from an IP camera.
I have a single for Form1 with a TVLIPCamera and VLImageDisplay component, the output pin of the TVLIPCamera component is connected to theinput pin of the
VLImageDisplay. I have set the URL property of the camera component to http://username:password@192.168.1.65/mjpg/1/video.mjpg
the code compiles and runs but there is no video displayed. Mitov advertises the TVLIPCamera component as suitable for use with a "generic IP" camera although the term "generic" is not defined.

I can test the camera with an web browser using the following URL  http://192.168.1.65 Which then prompts me for a user name and password,
after entering both, live streaming of video from the camera is displayed in the browser.
 I have monitored the network traffic to the camera with Wireshark and when the RAD C++ builder application runs, a TCP connection is made with the camera and Wireshark shows 9 TCP packet exchanges but then communication stops.
Any suggestions as to what the URL should be or otherwise what the problem might be would be greatly appreciated ?

The IP camera is a SANNCE Security Cameras Wifi 1080P which is manufactured by ANNKE
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Hi Experts.

Got a question we seem to disagree on amongst colleagues.

In "modern" Windows environment (2008, 2012, 2016) with multiple DNS servers within unique AD (let's keep it simple for argument sake and not talk multi AD or forests), what is the best practice when it comes to IP assigning.

#1. Each DNS server has itself (loopback) as unique DNS entry in the TCP/IP settings, and any second DNS is declared in the Name Servers tab.
#2. Each DNS server has itself (loopback) as Primary DNS entry AND any second DNS is declared as Secondary DNS entry in the TCP/IP settings.
#3. Each DNS server has the secondary DNS declared as Primary AND itself (loopback) in the TCP/IP settings.

All three scenarios seem to work 99% of the time, when it comes to AD replication mostly, but at times, we like to point fingers at each others config for any downtime that occurred, and subsequently buy a round of coffees for the team :)

Any Experts wish to comment ?
Cheers.
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What is the purpose of in-addr.arpa within Server 2016 DNS?

in-addr.arpa
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Within Server 2016 DNS Manager what are SRV records used for?

SRV records
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Within DNS manager, what are the values in the brackets "[ ]" within the Data column?

Data values
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We just switched to a different ISP provider a few days ago. Since then, there have been several Bad Address entries in the DHCP server (Windows server 2012). After deleting them, they'll appear again in an hour. Their Mac addresses are not shown in the address lease.

I used the DHCPFind to check if there's any other DHCP server on the network. The result is attached.

How do I find out what device(s) is causing the issue? Or How to fix this issue?
DHCPFindResult.JPG
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PMI ACP® Project Management
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PMI ACP® Project Management

Prepare for the PMI Agile Certified Practitioner (PMI-ACP)® exam, which formally recognizes your knowledge of agile principles and your skill with agile techniques.

Dear EE,

I have found warning at DB server when user has reported Application dis-connectivity.
 
1)  User reported Application Dis-connectivity Error as attached.
SQL Error

2) We investigate the issue and look in to the Event logs and found below WARNING. Event Id : 4227

TCP/IP failed to establish an outgoing connection because the selected local endpoint was recently used to connect to the same remote endpoint. This error typically occurs when outgoing connections are opened and closed at a high rate, causing all available local ports to be used and forcing TCP/IP to reuse a local port for an outgoing connection. To minimize the risk of data corruption, the TCP/IP standard requires a minimum time period to elapse between successive connections from a given local endpoint to a given remote endpoint.


Please confirm will user application error is due to this above error.

Thanks
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Hi!  anyone have any luck with a "TELNET" like connection with MS ACCESS?    I send simple text commands to a connected unit via TELNET.    By TELNET I mean using a communications application that converses with a connected device via IP address.     Something like sending "readbuffer01" and a response like "0,00.4,2" is returned by the conneted device.   I do this over a TELNET application like Tera Term set up for IP of the connected device xxx.xxx.xxx.xxx format for IP and TCP/IP port 3602 emulating a VT100 terminal.   Any way that ACCESS can send commands and listen for a response like these terminal programs.   I am basically trying to automate data collection over the tcp/ip connection and store in a form/table.

Thanks!
Brian
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Hi Experts,
How to grep connected tcp IP & Port connection then forcefully kill using batch.

example;-
netstat -a output is

Active Connections

  Proto    Local Address                        Foreign Address                State
  TCP       192.168.1.101:49366            192.168.1.55:65000          ESTABLISHED
  TCP       192.168.1.101:49475            192.168.1.55:64000          ESTABLISHED
  TCP       192.168.1.101:49384            192.168.1.55:63500          ESTABLISHED
  TCP       192.168.1.101:49396            192.168.1.55:22                 ESTABLISHED

Need to forcefully kill all TCP connection which is connected with 192.168.1.55
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I bring my (Windows 10 Pro) laptop around to do support in a few different networks - some with DHCP and some where a fixed IP-address is needed. Have tried to find a way to make shortcuts to set the fixed addresses (or set the network adapter back to dhcp), but haven't found a way to do it. Thinking of commands in a batch-file. Any suggestions?

-Olaf-
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Cisco Network Question:  2 vlans and one Internet connection

I need to set up a guest network for access to the Internet-only.  The network configuration is:
-  COX Internet
-  RTR_FW: Meraki MX64
-  Core_Switch: WS-C2960X-48FPD_L:  LAN-base
-  Distribution_Switches: WS-C3560CG-8PC-S: IP-base

We presently have one external IPv4 address and use 192.168.168.0/24 internally for operations.

The 2960X is a layer 3 capable switch.

Is there a way to route another network VLAN, something like 172.16.168.0/24, to the Meraki RTR Internet connection.  The Meraki is presently port mapping the external address to the 192.168.168.0/24 network with the Default router of 192.168.168.1.  I used a trunk to the Meraki RTR-FW from the 2960X and it works....

Or do I need to add a RTR and use two virtual interfaces?
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Hi All,

i need to listen on port for testing on a windows server. Do anyone know of a utiltiy? i used one before however unfortunetely i didnt keep a note of it.

Regards,
kay
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Today we faced the Email Delay issue on Exchange environment. Emails were delivering with 5 to 7 minutes delay. On investigation, we found following errors on server. It appears from the first error there could be some connectivity issue between the Exchange servers, but both the servers are located on same chassis, the chances of connectivity issue is very low. After restart the issue gone it also shows there was no connectivity issue. What could be the issue?

Error on Server Queue:
{LED=441 4.4.1 Error encountered while communicating with primary target IP address: "Failed to connect. Winsock error code: 10048, Win32 error code: 10048. "Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or deliver failed to all alternate hosts. The last endpoint attempted was x.x.x.x:475]

Warning on Server Log:
TCP/IP failed to establish an outgoing connection because the selected local endpoint was recently used to connect to the same remote endpoint. This error typically occurs when outgoing connections are opened and closed at a high rate, causing all available local ports to be used and forcing TCP/IP to reuse a local port for an outgoing connection. To minimize the risk of data corruption, the TCP/IP standard requires a minimum time period to elapse between successive connections from a given local endpoint to a given remote endpoint.
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How can I completely disable IPv6 from all network adapters on a Windows 7 Pro. computer?  The use this method to roll-out that configuration change to hundreds of computers?  Is there perhaps a script?

What I am looking for is to disable or un-check the ipv6 settings.

ipv6_1
I want it to be grey'd out or disabled.

ipv6_2
According to web page: https://techjourney.net/disable-turn-off-ipv6-support-in-windows-10-8-1-8-7-vista/

I have tried opening a command prompt as administrator and running
reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters" /v DisabledComponents /t REG_DWORD /d 0x000000FF /f

Open in new window


But after I run this command I think IPv6 is disabled partly; but, I still see the check mark on the adapters indicating that it is still enabled.  

Question1: How can I disable the ipv6 for all adapters on a windows 7 Pro. PC?  My manager specifically asked me to do the un-check box, to make it look disabled.

Question2:  How can I use that method for a mass deployment to change the config on hundreds of devices?

Question3:  How can I verify that IPv6 is indeed disabled?

Before the registry changes, if I ran an ipconfig all, under "Ethernet adapter Local Area Connection"  I saw
IPv4 Address. . . . . . . . . . . :  ###.##.##.###
Then I saw
DHCPv6 Client DUID. . . . . . . . : ##-##-##-##-##-##-##-##-##-##-##-##-##-##

After the Registry changes, I do not see any reference to DHCPv6 Client DUID. . . . . . . . : ##-##-##-##-##-##-##-##-##-##-##-##-##-##
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Wired users getting 192.168.1.x IP address.  Instead of 10.10.x.x
Not sure what happened.   Not all the users tho.  Any ideas?
ipconfig /renew /release not helping.  
Need some help troubleshooting.
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CompTIA Cloud+
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CompTIA Cloud+

The CompTIA Cloud+ Basic training course will teach you about cloud concepts and models, data storage, networking, and network infrastructure.

Hi Expperts,

Using PHP, JS, and/or jQuery, is it possible to detect if the user is using their registered device.

I think that every device world-wide has a unique MAC Address, so I guess maybe my question is how to read the MAC address? However, not of any modem or router, but of the endpoint device (ie-computer, phone or tablet)?

Thank you.
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Hi All,

I had capture the packet within our intranet where I place the sniffing tool at core switch to only capture conversation between all client to one server. I had observer the almost packet was captured is TCP SYN/ACK packet and TCP RST packet. The TCP SYN packet only below then 10% of captured packet. Its is abnormal in happen in this conversation?
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We recently changed a client's subnet from 192.168.1.x to 192.168.71.x.  All is fine, except that we neglected to change one of their devices to the 71.x subnet.  

We're remote now.  If we were onsite, we could change a computer to 192.168.1.x, connect to the device, and change its IP to 192.168.71.x,, then change the computer back.  But we're remote.  

If we change that computer's IP to 192.168.1.x, we lose internet connectivity.  

Is there a way we can still change the computer's IP to 192.168.1.x, but still use the default gateway of 192.168.71.1 to get to the device?  It's looking like we may have to go onsite to do this...

This is a very simple LAN; SOHO router/firewall.

Thanks!
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Hi

I'm having issues with Cisco Any connect VPN client not allowing remote connections, specifically ports 139-445.  Running port query is showing that there are some ports open but not ones for the IP address assigned to the virtual network adaptor.

We have the old Cisco vpn adaptor running and those ports are ok.

Ideas?

Thanks
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Our LAN uses 192.168.1.x IP addresses.  One of our vendors has just required us to connect to their VPN, then RDP to one of their computers to conduct business.  Their network also uses 192.168.1.x IP addresses.  Our network is small, so the effects have been minimal, but only by luck it would seem.  Sometimes we are forced to re-login to our own file server, and this is cumbersome and inconvenient.  How can we adjust settings on our end to minimize/eliminate IP address conflicts?  Our networking equipment is SOHO.  One perhaps obvious solution would to change our entire subnet internally, but that just doesn't seem like the best way to proceed.  Advice please?
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Dear Experts

to setup new office what IP addressing is recommended as it is common to use 192.168.1.0/24 but I would like to go for something different and this network will have to be get connected over the VPN from other location and they may be using 19.168.1.0/24,  this new network yet to be setup will have internal dns and dhcp and leased line and mpls connectivity. the total users or end devices within this network will not be more than 75, I prefer other than 192.168.1.0/24 is there a recommend/best  practice in selecting a particular ip addressing for private lan network please suggest,  is it good to go with 192.168.0.1/24 or something like 192.168.100.0/24 or any other ip addressing recommended please suggest.
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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.

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TCP/IP
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