Networking Protocols

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Networking software modules are interfaced with a framework implemented on the machine's operating system that implements the networking functionality of the operating system. The best known frameworks are the TCP/IP model and the OSI model. Systems typically do not use a single protocol to handle a transmission. Instead they use a set of cooperating protocols, sometimes called a protocol family or protocol suite.[9] Some of the best known protocol suites include: IPX/SPX, X.25, AX.25, AppleTalk and TCP/IP. Other protocols indirectly related to networking include the hypertext transfer protocol (HTTP) and its related technologies, Dynamic Host Configuration Protocol (DHCP), Domain Name Server (DNS) and other Internet protocols.

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I've usually tried to attract inbound traffic to one edge router over another by prepending AS numbers on the less preferred edge router. Are there other common methods to suggest that you'd prefer traffic at one edge bgp router than another?
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My understanding is for sockets, connect sets the destination IP address, and bind sets the return IP address.

What would happen if I created two sockets, socka and sockb, and did:
socka.connect(10.1.1.2);
socka.bind(99.0.0.1);
sockb.connect(99.0.0.1);

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If I now send some data to sockb, will the data go to socka and then will socka forward that data to IP address 10.1.1.2?
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Does anyone know what RADB routes are?  We are requesting a LAN public IP from the Internet carrier that was promised.  Now they give us run around saying the route set belongs to RADB and they cannot update RADB route sets.  If the customer wants their prefix [1.1.1.0/24] to be routed via BGP, they would need to contact RADB to have them update their route set.  
We do not need a BGP.  Just requesting a public LAN IP address.

Does anyone know what does prefix belongs to radb mean?  I'm running the Whois and looks like the prefix belongs to my internet carrier.  Not to radb some sort.
Does the carrier give me a BS runaround on this?  It feels like it :)
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Env: Cisco Nexus 9508 with an 10Gbase-LR SFP connecting to the carrier. For the last few days the interface has been racking up input errors and CRC. Hundreds ever few seconds. We've replaced the SFP and we replaced the fiber from the SFP to the patch panel.

What trouble-shooting methods do I have my disposal once the carrier gets on site? I've had these maddening all night affairs where the vendor says "we're all clean to our next device in Deluth (or wherever). Besides replacing optics, shutting/no shutting the interface, what other tools would help to isolate the cause of these errors? Thank you.

(BTW A tech at the data center tried to throw us a loop but the interface went down from UDLD. If there's a way to make a hard loop to us more informative that would be good to know too)
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Reading BGP Routing table

In BGP Routing table displayed below, I would like to know the meaning of "i" .
there is "i" under Network column and another "i" under Path column.

Thank you

BGProuting.JPG
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I am setting up our infrastructure to enable remote phones on a new phone system we installed. The phone vendor requirements were fairly simple, port forward UDP 443 to a device on our DMZ(the virtual machine). Easy, or so I thought.



Everything looks good from the Firewall end. If I plug in the phone, I can see the traffic hit the firewall, and be forwarded to the device lets say is 11.11.11.11. No issues I can see from the firewall end. It's a Barracuda NG F280, I have gone over it over and over with Barracuda support and they see nothing from their end.



The issue is that traffic never hits 11.11.11.11. I have set up a monitoring VM on my DMZ with wireshark, never see the traffic. The VM has a packet monitor built in so I can create packet captures on the interface directly, never see the traffic. If I run a netcat cmd for UDP 443, I see nothing. I see other traffic. If I ping 11.11.11.11 from anywhere else on the network, I see it. There is nothing between this device and the Firewall, except the VMWare hypervisor.



I am at a loss at this point. My Firewall vendor says it isn't on their end, my phone vendor says it isn't on theirs. I believe that to be the truth, but I don't know what else it could be. Does anyone have any ideas? Only thing I can think of is something in VMWare, but I have never seen VMWare block traffic like that before.

Some more info:

Seems localized in some way to port number. If I change my forwarding rule to port 3300 instead…
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I'm trying to understand the concept of port.

I know the standard port number for http is 80.

is a particular protocol, such as http , tied to a particular port and it doesn't work in any other port?
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Spanning tree and working production environment.

Greetings, my work place has spanning tree and I have limited experience with Spanning tree.  I was charged with setting up new Wireless controllers and to route internet only traffic through a specific "Internet Only" VLan.  I have setup the configuration how the vendor suggested.  Basically:

- Create DHCP scope and assign the DHCP Gateway to a VLAN on the controller (created for the Guest VLan).  
- Then create a Vlan for Internet Only and assign an IP address to that VLAN(From the DHCP Scope).  
- Then assign that Internet Only VLAN to an available untagged port on the Wireless Controller.
- The assign an available IP address from the Internet only VLAN on teh wireless controller.
- Then connect that port (0/0/3) to the Internet Only VLAN with its own separate connection.

The problem, is that the Wireless controller is showing that port 0/0/3 is blocking.  Port 0/0/3 is the port connected to the Internet Only VLan.

Port Status
-----------
Slot-Port  PortType  AdminState  OperState  PoE  Trusted  SpanningTree  PortMode  Speed   Duplex  PortError
---------  --------  ----------  ---------  ---  -------  ------------  --------  -----   ------  ---------
0/0/0      GE        Enabled     Down       N/A  Yes      Disabled      Trunk     Auto    Auto    -
0/0/1      GE        Enabled     Up         N/A  Yes      Forwarding    Trunk     1 Gbps  Full    -
0/0/3      GE        Enabled     Up         N/A  Yes  …
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I am looking to upgrade my router to a router that can handle a higher volume and faster, but the number is confusing me a little.

I currently have a Ubiquiti ER-X and looking at the ERPoe‑5, I compared all the specs [RAM, Storage size, 1518 byte packets] and the ERPoe‑5 is higher or same, except for 64 bytes packets which the EX-R the throughput and pps, same is with the CPU frequency on theses 2 the EX-R is higher [EX-R throughput 957 Mbps pps 1,400,000 and the ERPoe‑5 throughput 490 Mbps pps 730,000, CPU frequency ER-X 880 MHz ERPoe‑5 500 MHz both CPU core count 2]

Please help.
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I had this question after viewing Stuck in INIT/DROTHER.

I have the same problem? OSPF INIT/Drother between Cisco Switch L3 and Cisco Firewall ASA?
I checked everything all the configuration.It looks good however it doesn’t work? I don’t really understand why?
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Expert Spotlight: Joe Anderson (DatabaseMX)

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Hi Experts,

     I want to configure elasticsearch to a new IP address.  Currently, it is on a dev machine.  But I want to configure to a new IP address.

currently, in my elasticsearch.yml the current settings are

network.host:0.0.0.0

path.data : /var/lib/elasticsearch

path.logs: /var/logs/

inside /var/lib/  elasticsearch is link file to links to /mnt/elasticsearch

I want to install elasticsearch to new machine.  machine ipaddress is eg., 5*.25*.22*.1*,  

My questions are,

Do I have to install elastic search on this new IP address,

or can I set this new IP address as network.host path in the existing dev machine?

or do I have backup and restore to the new ipaddress?

Please suggest how to configure?

I had tried changing the network host to the new IP address, and copied elasticsearch folder to the new machine and set the path to path.data and I had set path.logs to new machine folder paths and restarted elastic search from the existing dev machine.

elastic search failed to start.

Please suggest how to configure the elastic search on this new machine.

With many thanks,

Bharath AK
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How does a website (or podcast) send out notification of updates?

I have subscribed to a sample podcast and see that I do get alerts (upper right corner of screen) on my MacBook. I have not yet verified those alerts only show up when I have Chrome opened, but that because I always have Chrome open.

Here is what I see under Settings as the Allowed sites.

Screen-Shot-2018-11-26-at-11.48.02-A.png
What is port 443?

Does this mean my port 443 is open to alerts from these two websites?

Please let me know how this works, since I am considering using this for my podcast. Or, if you give me the name of this type of communications, I can look for solutions which I can adopt to have this behavior.

Thanks.
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picI have router on a stick fa0/0.10 10.10.10.1/30 on R1 and an IP address assigned to R2 f0/0 10.10.10.2/30. I am trying to understand why I cannot ping R2 from R1?

pic
R1 config:
interface FastEthernet0/0
 no ip address
 duplex full
!
interface FastEthernet0/0.10
 encapsulation dot1Q 10
 ip address 10.10.10.1 255.255.255.252
!

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R2 config:
interface FastEthernet0/0
 ip address 10.10.10.2 255.255.255.252

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Wonder your folks opinion.  How do you approach this questions from executives.  
 "what do you think is better 74Mb DSL or 60Mb cable?"  :)
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What's the best way to setup Cisco 3850 switches by copying configs over the new one. 2 identicals are already in place.  
The additional will server same functions as access switches.
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Meaning of Port number in Show spanning Tree

in the output of the command below  I see:

 Port        1 (Ethernet0/0)

I wonder what Port 1 means?  I thought the port is the same as interface.

Thank you


SW1#sh spanning-tree  vlan 20

VLAN0020
  Spanning tree enabled protocol ieee
  Root ID    Priority    24596
             Address     aabb.cc00.0400
             Cost        200
             Port        1 (Ethernet0/0)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32788  (priority 32768 sys-id-ext 20)
             Address     aabb.cc00.0100
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Et0/0               Root FWD 100       128.1    Shr 
Et0/1               Altn BLK 100       128.2    Shr 

SW1#

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How STP influence the Traffic

on the diagram below, PC2 is connected to  Switch SW3 that has a blocked port on the link to SW1. Now Traffic from PC2 to PC1 will it go from SW3 to SW2 then to SW1 or it stiil can go straight from SW3 to SW1 then to PC1

Thank you
stp
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Please see the below in asr1000 trying to establish bgp neighbor. Do we have to use address-family ipv4? Thank you

router bgp 22
 bgp log-neighbor-changes
 neighbor 55.66.77.8 remote-as 33
 !
 address-family ipv4
  neighbor 55.66.77.8 activate
  neighbor 55.66.77.8 soft-reconfiguration inbound
  neighbor 55.66.77.8 prefix-list ine in
  neighbor 55.66.77.8 prefix-list out out
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DR(designated router) is for sending source message to receiver. I am not sure DR is located between source and RP, or between RP to receiver? Anyone can give some idea? Thank you
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Introduction to R
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Interface Multilink Vs Interface Virtual Template on Cisco Routers

I would like to know the difference between using the commands :
Interface Multilink Vs Interface Virtual Template

it looks like they achieve the same thing.

Any idea ?

Thank you
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Dear Experts

We have the application server ( CRM system web-based ) running on windows 2012 R2 which is deployed on premises behind the firewall. we have to configure CRM application to send mails to the customers through office365 email account hence network team has provided access only to smtp.office365.com and on port 587 and denied rest of the outbound or inbound access i,e no http or https access to this system.  
1. The CRM application is not able to send mails when the http/https is disabled for this system.   Through the CRM workflows we are able to send the mails out only when the http and https is allowed to this system at firewall .
2.  we are not able to convince the network team as they say we allowed outbound smtp.office365.com and 587 the issue would be at application side, they are asking explanation on why http/ https required,
can you please help me to understand on what all ports or access to be enabled at firewall for this system/server in additional to smtp.office365.com and port 587 in case of  INBOUND and OUTBOUND so that we can communicate to the network team please.
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I want to check my network and see if certain ports and protocols are already allowed through the firewall, is there a windows  tool that I can use to verify this before I poke on the firewall?

Thank you,
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Up to now, we have been running a fairly large peer-to-peer network of almost 100% Windows 10 Pro workstations with ONLY IPv4 enabled on the workstation NICs.  (There are 3 interconnected subnets with no name service shared between them).  Disabling IPv6 was done historically because using IPv6 in addition to IPv4 caused problems.  

Yet, more often now, Experts advise enabling IPv6.  Going along seemed perhaps a good idea.  And, in the sense of "if it ain't broke don't fix it", the hoped-for fix was to fix the Network list of computers in each distinct subnet - which has become more flaky/unreliable.  The experience with this was mixed as not all computers were switched to IPv6; i.e. not all subnets' workstations had IPv6 enabled.

We have since solved the Network computer name list problem.  So, there's a decision to make:
- "if it ain't broke, don't fix it" says to leave only IPv4 enabled.
- Expert advice says to also enable IPv6.  

It surely appears that "IPV6" in Windows is NOT simply an addressing scheme but also carries with it other things - things which I'm unable to list, but one hopes.

I have not had any trouble that I know of in enabling IPv6.  Yet, when one of the senior folks enables it on his own workstation, the network connectivity dies.  This problem survives a reboot and, yes, IPv4 remains enabled.

I believe it's bad practice to have a mix of settings in a network.  So if someone can suggest a fix to the network connectivity problem
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when I do a pptp VPN from my network over an ATT router I get this error only on my windows 10 devices (1 desktop and 2 laptops) via WiFi and via Hardline. my 1 win7 desktop has no issues and when I put the win10 devices on a different network (my hotspot) the VPN goes through with no issues. any ideas?

I've already tried disabling the win10 stations local firewall and that did not help.
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I am sysadmin..I want to know

I want to reach the server, to check the connectivity thru specific port.
This is just to varify whether the required firewall rule defined properly or not.
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Networking Protocols

11K

Solutions

16K

Contributors

Networking software modules are interfaced with a framework implemented on the machine's operating system that implements the networking functionality of the operating system. The best known frameworks are the TCP/IP model and the OSI model. Systems typically do not use a single protocol to handle a transmission. Instead they use a set of cooperating protocols, sometimes called a protocol family or protocol suite.[9] Some of the best known protocol suites include: IPX/SPX, X.25, AX.25, AppleTalk and TCP/IP. Other protocols indirectly related to networking include the hypertext transfer protocol (HTTP) and its related technologies, Dynamic Host Configuration Protocol (DHCP), Domain Name Server (DNS) and other Internet protocols.