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

netstat -a output is

Active Connections

  Proto    Local Address                        Foreign Address                State
  TCP            ESTABLISHED
  TCP            ESTABLISHED
  TCP            ESTABLISHED
  TCP                   ESTABLISHED

Need to forcefully kill all TCP connection which is connected with
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Can someone explain to me where consensus algorithms fit within the TCP/IP model?  Let use Raft as an example.  Does it use multicast?  Does it use it's own transport number or TCP/UDP?  Does it live on the application layer?

Hello Experts,
Seemingly out of the blue (starting July 29th), though possibly corresponding with installing VMware Tools on the server (7/22), or, less likely I think, updating our ERP software including telnet server (7/21) and OS updates (7/21 - see attached), our Server 2012 R2 VM has been acting up.

I have been rebooting a telnet server service daily for two years+ to kick out clients that didn't log out and had their then sessions hang, which frees up licenses for new clients to log on in the morning. Recently, this has caused the server to not accept new connections on port 23. Nothing seems to fix it except for an OS reboot. The corresponding message in the Event Viewer is from AFD:

Closing a TCP socket with local port number 23 in process 16584 is taking longer than expected. The local port number may not be available until the close operation is completed. This happens typically due to misbehaving network drivers. Ensure latest updates are installed for Windows and any third-party networking software including NIC drivers, firewalls, or other security products.

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This happens reliably now every time the telnet service is restarted. The process ID corresponds to the telnet server. Killing the process (that was restarted initially and caused this error) does not then allow connections on 23 - the OS must be rebooted. Disabling and then enabling the network adapter does not help. I reinstalled VMware tools which did not help.

Another error from Tcpip may be related started happening about a week later (8/7) and has been occurring daily or up to six times a day since:

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I would like to convert HTTP streaming HLS  to UDP or RTP, I  have tried VLC  and it works only in windows 10, does anyone  have any other software example that is validated  and is working properly?

I had this question after viewing Need to kill an application that is auto starting on Windows CE 5.0.

I have a remote device running Windows Embedded CE 6.   I would like to add some bench automation to this unit, but like most target devices ti has an autostart routine that puts an app on a touch screen with limited functions.    I am confident I can get the automation I need if I can only poke around in the file system of the target device.   I am trying to connect to the device remotely with a Windows10 machine, so activesync is out.  I did try a windows XP machine and activesync failed, so the target device is not set up for that.   That leaves TCP/IP I guess and a connection with Visual Studio tools?   Is there a better tool?   VS requires that I install Corecon files to the target, but if I could install files to the target, I would not need Visual Studios.....  The unit can be attached with OEM software to run remotely as well as firmware updates are installed via USB connection, so I am pretty sure there is an agent installed to the target that allows this.   The unit installs to devices under Windows10 as "USB Remote NDIS Network Device".  I apologize for my novice approach here, but I am more of a hardware gy than software.   I am willing to hire this hel pout if anyone knows a contractor that works with embedded windows.     Thanks so much for reading!!

Hi... Can anyone tell me what is this Simple Network Audio Protocol running on port 4752 ? Thanks
In the environment I am supporting for NGO's there are 2 Exchange Servers, an Exchange 2003 and an Exchange 2010 Server. On the Exchange 2010 Server since few days the router address is added to the IP Block List on the Hub Transport Server. Even after disabling IP Block Listing on the Organization Level the router address is added regularly to the IP Block List within Hub Transport on Server Configuration Level. Any ideas how to prevent this. Blocking does really block complete incoming mail traffic.

I started receiving TCPIP Event ID 4227 on two servers.  One server is an SBS 2011 domain controller and the other one is a Server 2016 Standard virtual machine on completely different hardware that only hosts a reporting software program.  These errors will occur at completely different times on each server so they don't seem to be related to one another at all.  The SBS 2011 server is running on it's own physical hardware, and the Server 2016 server is a virtual machine on a Hyper-V host which also has 6 other server virtual machines that are not experiencing this problem.

For troubleshooting, I have set the 'TcpTimedWaitDelay' to 30 in the registry on both servers and that did not fix the error.  I have also set up a script to run a netstat and get-process capture exactly when the error is logged in Event Viewer and I have collected the logs which are attached.  When looking through those logs I cannot determine what the issue really is since it doesn't seem to be related to the 'TcpTimedWaitDelay' setting.

At this time the error doesn't seem to be affecting any functionality on either server so I'm not sure how concerning this really is.

Any information is appreciated and if you need any further clarification on anything please let me know.

Thank you
I have two sites, both of which are connected to an MPLS that provides the VOIP and site-to-site data communications. The main site has dedicated internet (ASA 5520 and 2800) and is where the other site goes through via the MPLS. All of this is on the private side.

Both sites have regular 100MB/s cable internet for the public Wi-Fi in addition to the EOF/MPLS.

I want to add some redundancy for both locations in the event the MPLS or internet at the main site goes down and utilize the existing public cable internet service.

Looking for some suggestions for failover, using existing equipment or minimal equipment for site-to-site VPN connections. Not too worried if I cannot keep the voice traffic running, mainly a data/internet issue.

Thank you in advance.
dns3.jpgps assist why can't change dns ip address and apply register dns settings.
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Issue with high number of  TCP CLOSE_WAIT socket connections on Hortonwork(HDP2.6.4) NameNodes & Metastore Server.
We frequently have very high number of CLOSE_WAIT  socket connections on hadoop servers, as a result hadoop services are unavailable on Namenode servers. This happen after heavy ingestion of data in cluster. As a result, I need to restart the cluster after re-booting concerned servers.
I tried re-setting  value of several TCP attributes on the servers, but this had not solve the problem.
Using lsop | grep CLOSE_WAIT, I can identified concerned processes which had CLOSE_WAIT socket connections, I killed the concerned process & try to re-start hadoop services but this had also not solve the problem.
I had monitored the servers for number of CLOSE_WAIT socket connections & whenever number of these keep rising , it's point to symptom that the hadoop services on NameNode are going to down in couple of minutes.
Any idea to solve this issue is welcome.
I am needing a revolving server system that changes IP address once it starts getting hits from sever filters. It needs to be seamless and use the same email address that we establish to send emails out from, but configures a different IP with every 50 to 100 emails. This is what we need to get a marketing job done and the email messages we want to send have to fit the character count specifics and font type. The subject line is the most important and the size cannot exceed X kilobytes for the total email to reach target market.

Can you please advise why IP of server is changing like

Pinging with 32 bytes of data:
Reply from Destination host unreachable.
Reply from Destination host unreachable.

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Recently, our W2012R2 RDS server has started giving users problems logging in. The message is:
The number of connections to this computer is limited and all connections are in use right now. Try connecting later or contact your system administrator.

I'm having a hard time finding any helpful information on how to resolve this issue other than on desktop versions of Windows.

In a bid to get around this issue, I've opened more ports (HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp 339x), and this has given some temporary reprieve.

It seems to me that the issue is pervasive. By that I mean that the message does not disappear even if existing users log off from their RDS sessions.

This RDS server has been working fine for years, and now, suddenly, this happens.
We run a small network with less than 256 devices so we use static IP addressing (IP subnet
We recently expanded our equipment so I changed the subnet to on all existing servers, workstations, printers, switches, routers, etc to accommodate new workstations in the 192.168.1.? range.

Any workstation (new or old) that I change to the 192.168.1.* range has communications problems. Most notably drive mapping on logon and being accessed by remove viewing products like VNC. Each time I change a machine back to the 192.168.0.* range the problems go away.

Any direction on how to troubleshoot this issue would help !
Please include the detailed explanation of the following:
Physical layer
Data link layer
Network layer
Transport layer
MAC address
IP address
TCP port
Checksum check
Routing table
Hello All,

I have integrated Kamailio 4.4 with asterisk 13 LTS and I think its been properly integrated. It also shows me the registered users but when i call from 101 to 102 it gives me the below error

[May  7 12:43:14] NOTICE[19838][C-00000000]: chan_sip.c:25545 handle_request_invite: Call from '101' ( to extension '102' rejected because extension not found in context 'public'.

I have followed the below for installation and configuration.

The user database is fetching from remote host in which kamailio has been installed. Users are showing in asterisk node as well

asterisk*CLI> sip show users
Username                   Secret           Accountcode      Def.Context      ACL  Forcerport
101                                                          public           No   No
102                                                          public           No   No

So how can i debug this or is there any clue that what might be wrong. Please find below  the extension.conf details as well.

exten => _1XX,1,Dial(SIP/${EXTEN})
exten => _1XX,n,Voicemail(${EXTEN},u)
exten => _1XX,n,Hangup
exten => _1XX,101,Voicemail(${EXTEN},b)
exten => _1XX,102,Hangup

Thanks and looking forward for some clues from this community

Atif Ramzan
Public IP configuration for two different network. I got error when I assign public ip address on port 1 and 2 with same subnet. for port 1 and i got error when I try to set up on port 2, "same subnet on port 1" I am using Cisco 1926.  How do I make this work? Any advise?
I am getting error 1m ipv4 tcp listen drops
"the number of TCP listen socket drops during the last minute"
Last night i tried to enables https on server with following steps
Added virtual host file but i reverted the changes.
I also executed the following commands: is it efected something on server.
sudo iptables -A INPUT -p tcp -m tcp --dport 443 -j ACCEPTED
sudo lsof -iTCP -sTCP:LISTEN -P
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I'm sure this is simple, but I can't remember and I don't have time to figure it out, so...

I have a Windows 10 "All In One" lenovo computer.

The PC needs to connect to a small personal NAS via Ethernet, AND, the only way it can get Internet is Via Wireless.

The PC has both wireless and Standard RJ45...

I just can't remember how to do both at the same time.

Or, am I over thinking things: Just set a common IP for the RJ45 and the NAS , and then connect the wireless and I'm done...

Just not sure, and when I get there to set it up, it'll be too late to figure it out.

I have a law firm client who has a network for his suite of offices covering a whole floor, 192.168.101.x  The firm has two open offices so they leased them to a different attorney and his paralegal.  The lease included 'internet'. Because the main law firm has ample (100x30) capacity (and a limited budget) I tapped the network (as though it were WAN) into a little netgear wifi router (creating 10.1.10.x).  All this worked fine. Because of the double NAT, the 10.1.10.x network has slightly increased latency but it is negligible.

Last week the 10.1.10.x attorney's paralegal contacted me saying that the lease was supposed to include access to the firm's printer/copier/scanning systems (Ricoh, running Nuance software). It was easy enough to create credentials for them to Copy, and I set up a scanning protocol that uploaded their PDF's to BOX.COM. But they want to print large jobs on the Ricoh printers ( and - everything on the big law firm is Static IP with MAC-ID).

How do I create a printer path on the 10.1.10.x network (two machines, paralegal is Win10, attorney is Mac, both current rev) to and
I tried the below code and it showing output like SSH-2.0-OpenSSH_5.3 that means connected i hope.

 declare c  utl_tcp.connection;  -- TCP/IP connection to the Web server ret_val pls_integer;
 BEGIN c := utl_tcp.open_connection(remote_host => 'ftp.******.******.com'
                                   ,remote_port =>  21 ,charset => 'US7ASCII' --                              
                                   ,wallet_path     => '****************' --                              
                                   ,wallet_password => '**********' );  -- open connection
--  ret_val := utl_tcp.write_line(c, 'GET / HTTP/1.0');    -- send HTTP request
ret_val := utl_tcp.write_line(c);
BEGIN LOOP dbms_output.put_line(utl_tcp.get_line(c, TRUE));  -- read result
WHEN utl_tcp.end_of_input THEN NULL; -- end of input
Could someone help me on next steps on How to open and read the .csv file present in SFTP/FTP server and load it into Oracle DB table ?
We have a TCP/IP interface between a Millennium SPA POS system and Oracle Opera PMS system at our Hotel. There are a total of 8 interfaces and 7 of them have no issues. This specific one keeps disconnecting on the POS side. I have a packet capture that shows all traffic over the specified port and it looks like every 15 minutes exactly the interface disconnects.  On the POS side, we get an error message a pop up that must be clicked. Once you click ok on the pop up, the systems immediately automatically reconnect with out issue. As far as i can tell there is zero traffic unless someone is actually sending a transaction across. There is absolutely no keep alive being sent as far as i can tell.

I have attached a packet capture here.

I have not dealt with these serial/ip interfaces very often and dont really know what i am looking for in the packet capture. But it does look like the PMS system is sending a RST packet which from what i am reading terminates the connection.  Can anyone confirm this is what is going on based on the attached packet capture? I appreciate any assistance here. We have been battling this for 2 weeks now and both sides vendors are telling us it is the other sides problem.

Cloud based application having issues with ldaps bind to our Domain Controller in DMZ.
The application vendor is seeing the follwoing log entries on their side:
           [7:Public User][1024:application notice][R] (:) - Unable to bind to the LDAP server.

Based on this they have taken a wireshark capture and seen the following sequence of packets:-
Source -> destination (DC)   TCP    49662->636 [ACK] Seq=805 Ack=12910
Source -> destination (DC)   TLSv1  Application data
Source -> destination (DC)   TLSv1  Encrypted Alert
Source -> destination (DC)   TCP    49662->636 [FIN, ACK] Seq=927 Ack=12910
destination (DC) -> Source   TCP    636->49662 [ACK] Seq=12910 Ack=928
destination (DC) -> Source   TCP    636->49662 [RST,ACK] Seq=12910 Ack=928

They are saying that the reason packet analyser highlights the [RST, ACT] packets in red is because after the connection closure by Cloud Application server (source) [FIN, ACK] , server is expecting a final [FIN, ACK] from Domain Controller  (destination) but [RST, ACK] arrives instead. And thus they believe that it could be a issue with the Domain Controller.

Is this claim correct?
What can we do to troubleshoot this further?
Windows 10 Pro machine with a USB 4G card changes the TCP/IP v4 settings to a blank IP address when connecting to the mobile network. If I change this back to dhcp as soon as I connect again it reverts back. This is the second machine I have had this problem on and cannot find a solution.






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.