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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 have two questions about "under the hood" processes executed by Webrequest and the getresponse method.

1) I have noticed while packet capturing that, when doing a webrequest with a payload, packets starting a TCP/IP connection are sent and received *before* the getresponse method?  I would have expected the payload to be cached and sent only when the getresponse was called?

2) I have a webrequest case that has me puzzled.  It is an HTTPS URI.  All proceeds as expected (443 TCP/IP connection made before getresponse called) until the getresponse is called.  When that happens, the process attempts to create a new TCP/IP connection to the server, this one being on port 80 (not HTTPS).  Since the request is not HTTPS, the server ignores it and the process times out with a "no response from server".

What would cause the getresponse method to spawn a new connection, and why would it send it via HTTP when the original connection was made via HTTPS?  The certificate for the server is valid, and I have tried turning off the check-certificate functionality.

Thanks for any insight on both questions.

Bryan Hunt
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my network is as follows:


Sonic Wall - (gateway

Just double checking, I want the SonicWALL subnet to be private.  I am a little concerned because when I am on a workstation behind the sonic wall I can ping the Comcast gateway, and navigate to the admin portal.

However, when I am directly plugged into the Comcast gateway I cannot ping the 1.1 gateway subnet.  So the SonicWALL subnet is not visible to the main comcast network.  Is my network setup and secured as intended?
Need to access an application on a company Windows Server from outside using an iPad, Server has a private Static IP (10.x.x.x). The office router has Public Static IP interface. How can I access the server from outside on an iPad? Can I access the server using a public IP is this situation? Please advise.
I have a Juniper QFX. My infosec team wants me to disable the TCP timestamp as per the ID: 80091

Now I know how to disable ICMP timestamps, but not the TCP timestamps. And I don't want to disable it for the whole QFX. If it can be done for an interface, that will be awesome.

Any help will be appreciated.
Hello , does anyone knwo how to transfer iPhone contacts and messages to Android phone without any loss ? i've tried many ways to transfer them , but always fail ,and i don't how to connect the differen operation phones ,
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,
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 -->" -> SMPP SMPP Deliver_sm"
but we reply by -> TCP 42758 > dynamid [ACK] Seq=4141 Ack=52 Win=128 Len=0
That means are we losing frames.Pls help

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?
How to enable Mysql server access through TCP/IP
where mysql installed in Centos machine.,.I am trying to access using mysql workbench it through TCP/IP but throwing error .. attached screenshot.
Where as when I select TCP/IP over SSH .. I can able to connect .
I'm receiving this error among others, listed after. I have no idea why this error is coming up! how do I address?

Event 4879 MSDTC Client 2
MSDTC encountered an error (HR=0x80000171) while attempting to establish a secure connection with system SERVERNAME.

More errors that I don't understand and one that Microsoft doesn't even seem to know about (starting with that one)

The error that MS has no info on in Event ID Online help
Event 4230 TCP/IP has chosen to restrict the congestion window for several connections due to a network condition.  This could be related to a problem in the TCP global or supplemental configuration and will cause degraded throughput.
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Need to refresh DHCP IP address reassign Needed to command
I have an IPv6 box that is supposed to be routing via HE. I have radvd configured, so it hands out a /64 subnet as follows:

interface enp2s0
      AdvSendAdvert on;
      AdvManagedFlag off;
      AdvOtherConfigFlag off;
      prefix 2001:470:1f17:204::/64 {
            AdvOnLink on;
            AdvAutonomous on;
      # This is the DNS server on the internal interface
      RDNSS 2001:470:1f17:204:feaa:14ff:fe53:2eec {
      route ::/0 {

I have the interfaces up as follows: enp1s0 (enternal interface), enp2s0 (internal interface to LAN) and hurricane-ipv6 (interface to HE):

enp1s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet  netmask  broadcast
        inet6 fe80::219:5bff:fe2f:e30  prefixlen 64  scopeid 0x20<link>
        inet6 2001:470:1f16:204::2  prefixlen 64  scopeid 0x0<global> ...

enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet  netmask  broadcast
        inet6 2001:470:1f17:204:21f:c6ff:fe5e:58b1  prefixlen 64  scopeid 0x0<global>
        inet6 fe80::21f:c6ff:fe5e:58b1  prefixlen 64  scopeid 0x20<link> ...

hurricane-ipv6: flags=209<UP,POINTOPOINT,RUNNING,NOARP>  mtu 1480
        inet6 fe80::b847:c15a  prefixlen 64  scopeid 0x20<link>
        inet6 2001:470:1f16:204::2  prefixlen 64  scopeid 0x0<global>...

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet  netmask
        inet6 ::1  prefixlen 128  …
how to send and receive the message through in tcp/ip using servlet

I have an interesting setup. We switched to a hosted voip solution but for our emergency analogue lines we purchased two fxs vega 3050g gateways.

I have successfully configured the dialplans between the two units without the freepbx box as an in between. It is such a simple setup to just have it dial our security desk the pbx was not needed.

We are getting ready to deploy but have two lingering issues. To route calls between interfaces and the two gateway devices you have to initiate the sip handler to apply codecs and handle advanced features like call waiting. So dialing by IP between devices or loopback on between interfaces.

The one limitation I am running into is only one call at a time will take place between gateway... almost like the port is busy or it can only route one call at a time between gateways. Similar issue happens when trying to use call waiting... the first call connects but when I initiate the second call I get one indicator tone then the call fails with a cause code 41 (temporary network error)

Is this a matter of me needing to use more than the default udp port 5060 or am I just missing something here? I'm not a phone guy so I have a slight learning deficit.

I have combed through sangomas support site and manuals and found nothing like this... their support has yet to offer any solutions (on almost any of the setup.. which is troubling) so I'm turning to the community.

Thank you in advance
(1) how can i know subnet mask & default gateway of any ipv4?
(2)Explain  dns server in detail?
devices behind a switch are not able to acquire DHCP. when i assign a static IP it works OK.  the switch is connected by fiber optic to a core switch where the DHCP is configured
we have a TZ-210 wireless that need to change a couple of things on.  

We are connected to a comcast business gateway device.  It has wireless and we use that as an outside wireless,  It is not setup to access the internal network.  When we setup a laptop of phone we use that for VPN testing and remote connectivity.  I have 2 issues.

1. I cannot connect to the management interface on the modem, it is the default  It keeps getting dropped in the firewall.  What rukes do I add to tallow this?
2. We cannot send email from our mobile devices when connected to the Comcast wireless.  I would expect it to be a rule as well, but I'm not sure what to add to make this work.

We want to keep the comcast wireless off the internal network. But we need to access the management interface, plus some of the users need to be able to send via exchange when using devices or phones and sending exchange email.

I have 5 IP's assigned by AT&T to me on my On Demand Fiber circuit, but I only have 1 public address to the WAN. How do configure my 3 TZ300 to each use one of the assigned IP address and each to be a DHCP server?
Here's my scenario.  I have two networks and I need to combine them, ideally using Cisco SG300.  
Basically, LAN1 nodes need to be accessible to the LAN2 devices.  
To be exact, LAN2 computers need to be able to "talk" (TCP inbound and outbound) to the LAN1 computers on different ports.

Please see the diagram.  

I think I need to create two VLANS but not sure about the details.  Is this even possible with this switch?


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I have TDA200  I have made no restriction for Landline & Mobile and restrictions for International calls

I want to know...for dialing an international call it should be in such a way that they should be able to dial it with Code only. I want

to know the steps how to do it
I have a client who uses cloud hosted VOIP service provided by a respected uk based voip provider.

My client is based in a managed office where the network is managed by a 3rd party company. My clients has been experienceing intermittant issues with the phones and they have asked the network people to check that the firewall\router\vlan configuration is suitable  for voip traffic.

The network people have come back saying :
I have reviewed the data captured yesterday, the problem IP address 109.*.*.70 is registered to THE VOIP PROVIDER. This is passing tiny data fragments through the firewall which is flagged as a security threat as this method is also used to hack routers and firewalls, this throws up an alarm and is blocked.

They have suggested we ask the VOIP provider why this is happeneing.

I am not a networking or VOIP expert. Can someone explain more about this and perhaps suggest why these "tiny data fragments" might be occuring?
ipconfig \ all =>

Two IPv6 addresses, one is temperate with me from the speed test , question :  who is holding the first IPv6 ?  ISP or Unknown ?
where to find its mac address ?  Could it be rewritten my computer mac then, getting the 1st IPv6 then release the 2nd IPv6 to my modem while from IPv4 both sharing the same public IP by ISP .

two IPv6 who is first IPv6 where find its mac address ?
I have a EPC3940 Wifi-router, but its reach is insufficient and so I want to add an access point (DAP2553). It is already connected, and it has an SSID, and it gives IP-addresses to phones and tablets (or probably the dhcp server in the router does that).
I want to configure a few things on the access point but I cannot get in the configuration page which is supposed to be at

The IP-addresses on my LAN are currently
Internet IP Address: / 24
Subnet Mask:
DHCP Server:       Enabled
Starting IP Address:
End IP Address:

Please tell me what to do

A last remark. The access point (DAP2553) is connected to my router and functions, it gets an IP-address from my dhcp, but I cannot configure it. Also
I have a network using subnet mask, and the adresses are 192.168.x.x, the Gateway has the ip address

We are experiencing a routing issue with segment 1. For instance, we need to print from a server to a workstation, the server has the ip, and the station is

A ping from to goes timeout. A traceroute shows a route going trough the Gateway despite the subnet mask.

Any clues?
Using Ubiquiti For Wifi.

I have a vlan setup on a juniper switch with an ID of 17. The network ip is to the gateway of that port.
My reg network is scheme.  So here is my issue.
I have setup on my unifi controller a wifi network that ties to vlan 17, when it hits that vlan it hits the juniper switch where the vlan resides. However the issue is its not pulling the scheme, its pulling the scheme instead. Only reason for the vlan was to sepperate my wifi clients vs the hardwired clients. The DHCP server i am running is Windows Server 2012 R2. I have set the static route on the server to hit the switch but for some reason it will not pull an ip from the DHCP server with  . I dont know what im doing wrong. I have set also in my juniper switch the bootp helper for the particular vlan to go to my dhcp server at I dont know what else to do . Do i need the unifi router for this functionality to work ? Thanks for your help in advance.
Unifi layer 3 8 port switch.
Juniper Ex200 Switch
Windows Server 2012 R2






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.