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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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I need to add the following IP addresses to the A record of autodiscover.companyname.com within my Server 2016 AD domain:

        2603:1036:906:14::8
          2603:1036:3:66::8
          2603:1036:804:20::8
          2603:1036:101:4c::8
          2603:1036:906:84::8
          2603:1036:b00:15::8
          2603:1036:405:2::8
          2603:1036:101:2::8
          40.97.134.216
          40.97.121.8
          40.97.185.24
          40.100.162.200
          40.97.136.200
          40.97.124.40
          40.97.132.40
          40.97.115.56

What is the process to add all of these IP addresses to the DNS A record of autodiscover.companyname.com within my Server 2016 AD domain? All of these IP addresses need to be added, not just one.
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Does anybody know the exact function/meaning of the Windows regedit setting
  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\StrictTimeWaitSeqCheck

I find no real documentation from Microsoft, but some sources state something like:
  "This key tells the system to wait for TCPTimedWaitDelay to pass before reopening a socket."


It sounds like that would be applicable only for creating new outbound connections, not for responding to inbound connections.
Is that correct, does anybody know?

Thus, TCPTimedWaitDelay affects handling of both outbound and inbound connections, but StrictTimeWaitSeqCheck only affects outbound connections?

And if not - why bother with StrictTimeWaitSeqCheck at all. Why not just set TCPTimedWaitDelay to 0?


Also, in addition, I cannot find any formal Microsoft documentation on the default value for TCPTimedWaitDelay. Some sources say 240 seconds and some say 120 seconds. My test results lead me to think that the default value changed at some time (when?) and at least since Win2012 it is 120. Any ideas on this?
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I've got a normal MS (IIS8) web serve (IIS8 on Windows 2012), to which client browsers connect to request html pages.

One client (or rather its proxy) behaves like this:
1) Outbound connections use a quite small port range
2) Connections in time-wait ,or where the other side is supposed to be in time-wait, are reused for new outbound connections after 60 seconds (the web server uses 120 seconds for this setting, hence the incompatibility)
3) New connections initiated from the client do NOT use a TCP sequence number that is always larger than the last packet sequence number on that particular src/dst pair. Instead a completely random value is used as initial sequence number.

Issue 1) means that the client quite often makes the web server run into a "port re-use" situation, such that a new inbound connection is using a src/dst port combination that has already been used before (the server port is always 80, of course)
Nothing bad with this, though.

Issue 2) means that the the port re-use according to 1) sometimes occurs while the web server is still in time-wait state for that particular src/dst port pair.
This is a problem, as the web server will then not accept the request for some more time (until the server time-wait timeout period finishes), and the client will end up retransmitting its SYN connection attempt during that time, delaying connection.
However, that would not be so bad if it wasn't for issue 3)

Issue 3) means that when 2) happens, the web …
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What are the least expensive internet domain registration services?

I have a couple domain names I am interested in registering internet domain names and am looking for the least expensive way of doing this.
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HI,
I have tried almost everything on the Internet, I am not sure what am still missing.
PC: Windows 10
Router: Port forward enabled with UnPnP

The webserver is a Datasnap REST webserver, (might be irrelevant), hosted with IIS on windows 10 PC, and its accessible to localhost as well as different computer on same network, However its failed to get connect to when accessible via public ip:port  even on same pc.
Tested the port which is listening correctly. I put firewall and Antivirus off for the test.

Please help.

Thanks and Regards,
Vijesh
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Hi Networking Gurus,
Sorry if i sound stupid but i am very new to networking.My application work as ESME  for the smsc  and it seems that recently we observing huge delay in ack of submitted  message or ack not coming at all.I can see in netstat output of linux send queue is increasing hugely.Taken a tcpdump in which i can  see to much [TCP Dup ACK],[TCP Out-Of-Order],[TCP Retransmission]

Also i see in wireshark
Smsc send mesg with seq:1 ACK:1 Len: 51 -->"213.132.40.140 -> 192.168.40.8 SMPP SMPP Deliver_sm"
but we reply by
 192.168.40.8 -> 213.132.40.140 TCP 42758 > dynamid [ACK] Seq=4141 Ack=52 Win=128 Len=0
That means are we losing frames.Pls help
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I need help or some guidance for the following issue.

We use a VPN connection when we connect remotely. For software installations, we use an internal web server which we have no problems connecting to when we are at work. However, I am unable to connect from home.

One of the first things I did was to traceroute the host using the LAN connection at work:
  1     1 ms     1 ms     1 ms  chlz-fw01.net.**.** [10.39.41.1]
  2     1 ms    <1 ms    <1 ms  10.39.44.1
  3    20 ms    26 ms    20 ms  10.0.0.1
  4    21 ms    20 ms    20 ms  195.143.73.33
  5    21 ms    31 ms    20 ms  xe-10-3-1-5779.******.interoute.net [194.150.37.65]
  6    21 ms    21 ms    21 ms  10.96.31.111
  7    21 ms    25 ms    21 ms  10.96.20.17

Open in new window


When I connect from home with a VPN, I receive the following reply:

Tracing route to itappstore.**.** [10.96.20.17]
over a maximum of 30 hops:

  1     *        *        *     Request timed out.
  2     *        *        *     Request timed out.
  3     *        *        *     Request timed out. 

Open in new window


.. and it stops after 20 hops / with the same response

Next, I used the following command:

> nslookup itappstore.**.**
Server:  itappstore.**.**
Address:  10.96.20.17

DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** Request to itappstore.**.**timed-out

Open in new window


So it looks like the problem might be the DNS server.

Because the IP and DNS addresses are assigned automatically,
the adapter setting won't show the addresses.

I also tried an arp command and I get the following reply
> netsh
Server:  GBLDC1-GC01.**.**
Address:  10.96.16.6

*** GBLDC1-GC01.**.** can't find netsh: Non-existent domain

Open in new window


Is this a DNS issue?
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Hello I have a digital signage software server to remote led screens ..its   a web sever run on port   777  and 5222 it was work fine for few months my puplic ip was started by .195.xxx.xx.xx but now  it's stop i cant ping my pulic ip and all the ports is closed when I checked them by can you see me . Com now my public ip start by 63.xx.xx.xx what I can do to run the server again


Thank you
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I am facing internet sharing problem in my broadband connection.I gave connection to 4 users . and each user in connect with own router . I am facing with one user cable . When i connect his cable to my broadband modem port then all users including me getting IP of this user router and no one is able to use internet . When i do unplug cable from port then Internet is working fine .

What type of problem is this ?
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One of my client computers is giving us difficulty when trying to RDP into it.  I can ping the machine & get a response, where I'm confused is the IP that's returned doesn't match the host name.  I ran ping -a to check this, which returned a host name that was joined to a domain that has been decommissioned for well over 4 years.  Ran nslookup of IP it returned the same odd host name joined to the current domain.  Then I ran nslookup using the odd host name it then returned the odd host name, joined to old domain.
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We have a Class C network and are running out of IP addresses.  We have multiple switches throughout our company and don't want to incur the expense of upgrading all of them to be VLAN capable.  In order to expand our addresses, is it possible to only upgrade one of our switches to a VLAN capable switch and configure it as follows:
1.) The DHCP server is plugged into one of its ports which is configured to be on the default VLAN.  
2.) Any other switch plugged into it will be plugged into a port configured to be on the default VLAN.  
3.) Any other device (printer, computer, etc.) plugged directly into it will be plugged into a port that is configured to be on a secondary VLAN.
4.)  The DHCP server is configured to hand out a different scope of addresses for devices on the secondary VLAN.
5.) The switch is configured so the VLAN's can communicate with each other.

Again, if all we need to do is expand out addresses, is it necessary that any of the other switches are VLAN capable?  Does anyone have a alternate, perhaps simpler way of expanding the addresses?  We could convert to a Class A or B network.  Please advise, and thanks in advance.
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in order to configure tcp/ip you must install and enable a network adapter card server 2012 (Dell Server R430)
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I am looking into using Verizon's Cellular network to gather telemetry data from remote locations. Their data is of course not free.  

I did some simple testing using a Ethernet radio link I already have and saw that to send or receive 4 bytes of actual Data i care about, takes over 170 bytes of traffic to complete the transfer. I will usually only need to gather 200 bytes of data per poll (several times per minute) and I imagine the overhead (166 bytes) will be roughly the same size whatever payload I am sending. But as I currently envision it, that's going to wind up being a third of my data fee. And that doesn't account for whatever overhead Verizon has to add just to send it through their network.

What, if any, tricks can i use to minimize the traffic?
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Hi everybody i need write  modbus tcp/ip with vb all version

some people can help me? Thank You.
 
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I didn't want to hijack a thread so I created a new one. Here is a link to the original thread: https://www.experts-exchange.com/questions/26724470/Sonicwall-WLAN-to-WLAN-Printing.html

I have a SOHO wireless-N
I have WLAN to WLAN open any any any.
I followed the solutions from the other thread with no luck.
Here is the kicker, this setup worked for over a year with no problems.
We assigned 4 ShoreTel phones static IP's and instantly our wireless to wireless printing stopped working.
We have it set up to use TCP/IP printing. The printers don't show up when you go to setup a new printer.
When you run the TCP/IP method it finds the printer and selects the right drivers.
When you send a test print it starts the print job and then after printing about 1/8th of the page it stops and says print job failed.
It will then endlessly try to print the same test print until you cancel the print job.
I have hard reset the printers, I tried giving them static IP's. I called the manufactures etc.
When you connect your laptop to the LAN it works perfectly. Wireless it has an error every time.
It has to be something with the sonicwall. I just don't know enough to figure it out.
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Hi everyone

The company I am working for installs its images/OS via a network in UEFI.

How does the computer know on which server the image is stored?
Does the computer send out special packages via TCP/IP to retrieve the location of the images?
What protocol does it use?

I would also be grateful for a link to a site which explains the procedure.

Thanks

Massimo
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Environment:

 It is a small office with a windows 2012 R2 standard that is configured as a Domain Controller, DHCP, DNS and file and print server.

The DHCP scope is 192.168.168.2 to 192.168.168.100.
All workstations and other devices including DVR and VPN clients get their IP from DHCP dynamically or there is a reservation for them such as DVR, therefore I can see all devices under Address Leases in DHCP Console.

An annoying device seems to have dynamic IP and it is in a range of the DHCP scope (192.168.168.11) , however the DHCP does not show it under Address Leases.
The Arp command indicates that the IP is dynamic. The Advance IP Scanner under find it but cell under NetBIOS group, User and Date are blank The only cell is the Manufacturer and MAC address. I looked around and I don’t see any device that be manufactured by NetGear and the more confusing is that when at the server I run Arp command it indicates that the IP type is Dynamic. so I must assume there is another DHCP server in the network such as router/firewall but I use SonicWall and the DHCP services is disabled.

Can anyone help please ?
Advance-IPScanner-Result.docx
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what are the things to check before IP change on windows server?
How to find what all application has IP hard coded? any tools to find what all application are dependent on old IP?
Change of reverse lookup ip on pointer record and host A record and static IP on server and anything else need to be change after changing static IP on server
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Hi.  We are recovering from Irma and I have noted a strange issue on a few networks where their internet went down.  The specific account I am concerned with is configured as following:
Netgear Router bridged to Comcast Modem - Router 192.168.16.1
2011 SBS Server - DNS, DHCP & AD - file sharing   IP  192.168.16.2

I have configured the workstations to use the following configurations:
LAN IP (each PC has it's own) 192.168.16.10-16
Subnet: 255.255.255.0
Gateway: 192.168.16.1

DNS:  192.168.16.2

After setting this up on each PC, I still cannot connect to, nor ping the server or the other devices on the network.
They should be on a domain network, and they are definitely NOT home or Public at the least.

As this has happened on different networks, and the common link is they are Comcast and this has happened since we lost internet (it is popping in and out intermittently).  I just need to get the workstations to talk to the server.

Any ideas or insights?
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Google Photo's "Backup & Sync" tool is making my internet connection unusable when I'm uploading photos from my desktop.  I have another desktop & laptop, all on the same WiFi.

I do see I can limit upload and download speed.

QUESTION:

If the desktop is the only device requesting bandwidth, I presume that would get all of the bandwidth.

However, when I start using my laptop, shouldn't it share the connection and play nice?

My Comcast is normally 30 Mbps down and 5 Mbps up when I'm not uploading.

When uploading without specifying a limit, it can drop to under 1 download and 1 upload.

I just specified a limit of 400 KB/sec and download limit to 1800 KB/sec to see if that helps.

Thx
Mike
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Please explain the usage of the Multicast ip addresses below

I have seen different Multicast IP addresses used , the most common are shown below. Correct me if I am wrong

224.0.0.1 : I believe this is used by the IGMP querier to  find out if there is any receiver interested in Multicast.

224.0.1.40 : Probably this address is used by the IGMP querier for Auto-RP discovery (it is a little bit vague)

224.0.0.13 : probably this address is used by the IGMP querier when it is configured to use PIM protocol (I am not sure if it is specific to PIM version 2 or any version)

224.0.0.2 : is used by IGMP host (the Receiver) when it leaves the multicast group

224.0.0.22 this is used by IGMP Version 3 receiver, But I am not sure if it is used when the receiver leaves the Multicast Group or it uses it in different circumstances . (please clarify)



Thank you
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Hello,

We use an RDP session through a VPN tunnel to connect to our hosted software out of state.

We constantly experience latency through all of our VPN tunnels.  I can run a constant ping from our hosted provider back to our environment to get a small picture how bad the response times of the pings are.

The ping times will be consistent for a little while hovering at 55ms - 67ms and then we will see "request timed out" multiple times and then ping times will rise.  It seems like the ping times fluctuate a lot  (I assume they would as the signal is traveling through multiple possible connections).

When ping times are at 55ms or less everything seems fine.  However, when it goes up from their end users report latency.

We are not hard lined to our ISP as everything is wireless.  Our internet pipe should be sufficient at all locations as we have spoken with our ISP and we do not hit the high water mark on our bandwidth - only rare spikes the main site.  

We are not hitting the high water mark on bandwidth usage at any of our other sites.  Is there a good piece of Enterprise level software that one could use to help get a clearer picture of where the issue occurs?

What kind of architectural questions should we be presenting to our ISP?   To our hosted provider?

1.  Is your VPN Server over-utilized?
2?
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I need to register a couple internet domain names.

What are the lowest priced internet domain name registrars?
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Please help me understand about ARP.
I know the local ARP table is cached and records also can be manually added. But how come when I ping a remote IP it doesn't automatically create a corresponding ARP table record?
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Hello ,

I have 2 questions about timestamp ;

1. I have try to convert time stamp value to normal time but it was returned anormal dates :) what is the format of this TS val ?
2. As far as i read on the http://www.networksorcery.com/enp/protocol/tcp/option008.htm 


This field is only valid if the ACK bit is set in the TCP header.


but nearly all SYN packets in normal traffic not a DDOS has TSval  while ack was not sScreen-Shot-2017-08-27-at-18.05.41.pnget
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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.