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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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Need to refresh DHCP IP address reassign Needed to command
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Hello Everyone!

We had some security cameras installed and the installer asked me to open port 8000 for the dvr.  We have a Sonicwall 1260 Pro and I followed the instructions for port forwarding.  I created the service for both TCP/UDP, port 8000 and then created the group.  I used the public server wizard to allow public access to the camera ip.  After everything was complete I used the site,, to check if port 8000 was open.  Unfortunately, the port is still closed.  I'm stuck figuring what I could be doing wrong.  We do have 2 static ips for the site.  The other ip is used for the fax machine line.  i don't know if this could cause the problem.  Any help is appreciated.

Router: SonicWall 1260 Pro
ISP: Cox
Camera IP:
Port: 8000
We have an odd situation.

It's a hodgepodge network in a franchisor's location.

It's technically administered from head office on the other side of the country but they get me to do some of the work as I'm less annoying than the main IT.

Windows Server 2012 peer-to-peer system

#1. A windows 7 Professional station gave hard drive warnings (failure imminent) and infection notices
#2. Took station, cloned drive onto SSD
#3. autologon for computer was now erroring out. Had no idea what old password was, created new one with autologon in the registry
$4. Disinfected computer via Malwarebytes and installed Barkly endpoint
#5. Find out that the server is used to access 3 shared folders via peer to peer on the station and that it can't access the shares

At this point I figure that the issue is simply related to the password change, but no.

The server is unable to ping the station, either by name or by ip address. However, the station can ping the server by both name and ip address.

It looked to me as if DNS was incorrectly configured on the server (typo), so I fixed. ( to

#1. I've tried repair network on both.
#2. ipconfig /flushdns on both
#3. rebooted one or both after each or every other change
#4. turned off homegroup on station
#5. changed station network type from home to work
#6. created hosts file entry for station name to ip address
#7. tried to ping TCP/ip 6 address (no go)
#8. checked for saved credentials on the …
Hi guys,

I am a network engineer and I have a requirement where I was asked to design IP PBX system with  Analog phones
can I use cat6A cable, CAT6A patch panels or I have to consider 110block?

Can anyone please guide here, it's very urgent...........
Very bizarre issue. Details:

1. A customer on fibre-optic high speed Internet (via ISP-provided router) cannot connect to nor ping a mail server at
2. I arrived there with my own laptop, tried both LAN and wifi, and also could not ping the mail server.
3. I remoted into 3 other computers from his house, and from those remote computers, pinged the mail server just fine. These two other computers are in the same city as my customer. Two use the same ISP as my customer.
4. The ISP apparently logged in and checked his router - they say all is fine, and they have no idea why this would be happening.
5. Except for the inability to reach the mail server, the connection is completely fine - can get anywhere on the Internet, etc.

I seem to recall having an issue like this years ago, and it had something to do with routing at the ISP, but cannot remember any details.

Has anyone ever encountered anything like this?  I'm going there in two days to do a full reset of his router, but not confident this will be the cure.

Let me start off by saying I'm in no way shape or form a network engineer. I am an IT Generalist and I'm in the process of trying to figure out why some remote IP phones have stopped working for a client. I don't want to get too into the weeds, but I've looked at and compared traffic from working equipment to this non working system. What I've seemed to have boiled it down to is:

Working: Phone tries to communicate on Port 6801 with server, server sends RST, ACK - phone then tries Port 6802 - same. Finally phone tries port 6800 and everything works fine.

Non-working: Phone tries to communicate on Port 6801, receives back a RST (without ACK). Phone continually tries to communicate on port 6801 until it reboots and starts over.

I've captured traffic at the server, at the firewall and at the phone. It seems like the packets are leaving the server as RST, ACK, leaving the Firewall as RST, ACK but arriving at the remote location as RST.

I'm looking for ideas on what could cause this?
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
I am able to send email to gmail (of course) although it does show up as spam, outlook flatly rejects the .loc domain... but still cannot send between two .loc domains in lab..

I created two domains, dc2016.loc and dc2016a.loc (using 2016 essentials as DC) I have added both domains to the accepted domains list however, when I attempt to send to either of the two .loc domains, the email gets rejected as, unable to locate a valid address...

Looking at the recipient Information in the Queue Viewer, I am seeing Last Error: [{LRT=};{LED=};{FQDN=};{IP=}] even thought I have added them as accepted domains...Any thoughts?

I have just added a virtual private NIC to both exchange servers, and added appropriate send receive connectors on each

I have both NICs setup to Enable NetBIOS over TCP/IP as well but still having this issue... any thoughts?
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(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
I had this question after viewing SonicWall SOHO VPN site to site setup.

ID: 415306722016-03-3
If that is the case then you want the IP Address of the SOHO to be the Gateway address of the Comcast and the Gateway Address of the SOHO to be the IP Address of the Comcast. Then when you set up the the VPN you set it up with the IP Addresses of the SOHOs. Seems a little weird but that is the way it is done."
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?


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 ?
Portable, direct connect server access
Portable, direct connect server access

The ATEN CV211 connects a laptop directly to any server allowing you instant access to perform data maintenance and local operations, for quick troubleshooting, updating, service and repair.

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
The condominium i stay in have an incoming fiber cable, that is switched to LAN cables, one cable per condo. The system is like in an hotel, you must log in every time you need the service. What hardware and software would you recommend so instead each separate connection (lan cable) is closed or opened depending on the tenant paying or not paying, and no logon, logoff is needed?

we have 20Mbps internet link ,

I see a single user out of 70 users utilising almost 10Mbps BW by downloading 1Gb file in peak business time so that would like to restrict BW upload/download speed to min 1Mbps to 3Mbps speed.

Technical Details  :

- User desktops / Laptops connected to Cisco 3560 switch and cisco 2960 switches (both L3 and L2 switches)
- All ports are 100Mbps

I have done below testings :

- googled & verified experts-exchanges for my requirement

Test :1
- I have got info related to srr- shaping & srr-sharing and Limit BW commands but not worked , configured commands and verified ,still user get morethan 10Mbps output speed

Test 2 :

- Configured  policy MAP using class maps based on source IP and MACtraffic and applied to Switch port
   Policy map to "Input" accepting but policy map for :output"  not supporting , though requirement not fullfilling.

My Requirement :

- On each cisco switch port , would like to configure QOS : BW restriction Policy , say each user switch port should restrict min : 2Mbps to Max : 3Mbps upload / download  internet speed

- Is storm-control feature helps here ?
- Pls advise have any one ever practiclly worked on this kind of requirement , if so pls advise with sanitised configuration

Ramu Ch
/sbin/tc filter add dev eth2 parent 1: protocol all u32 match ip dst flowid 1:2048
/sbin/tc filter add dev eth2 parent 1: protocol all u32 match ip dst flowid 1:2049
RTNETLINK answers: File exists
We have an error talking to the kernel

we are getting this error after adding the flowid 2049 however we are moving in sequence numbers





Articles & Videos



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.