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Questions tagged [network-protocols]

The tag has no usage guidance.

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1answer
59 views

What exactly happens when a TCP segment is sent to a broadcast address?

Does the segment get delivered -- and the recipients are supposed to drop it? Does the segment get dropped at the (layer 3) switch/router? Or something completely different? Explanations or "RTFM!" ...
1
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1answer
29 views

Why does LAN stops working if switch is connected to two upfeeds?is [closed]

If I connect my switch to two upstream feeds from my ISP, my internal LAN stops functioning (see illustration below). What is it in the TCP/IP protocol that is disrupted to cause the above? ...
0
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0answers
48 views

TR-069 How to connect multiple ACS servers to a single device (CPE)

In general in the device (CPE) configuration there is only one field to set the ACS URL. But am in a situation(long story) where i need the device status and data to be sent to 2 different ACS servers(...
0
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2answers
39 views

Prevent Unjoined-to-domain computers from connecting to my network

How to prevent any computer that is not joined to the domain from requesting any service from my network? Considering that the computer is on another network.
0
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0answers
13 views

Looking for a detailed frame explanation of IEC 60870

consider the following scenario: A bunch of different controllers is sending information to a common sink, while making use of different protocols such as Modbus, Profinet, etc. Now this sink has to ...
-1
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1answer
219 views

Security issues with SMTP

I am looking at SMTP and POP3 and am trying to find the security issues with both protocols, I have found that SMTP can be easily impersonated on port 25. However I am struggling to find security ...
1
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0answers
61 views

How does VXLAN prevent duplicate MAC addresses?

It seems to me that VXLAN network identifier(VNI) works silimar to a prefix keeping identical MAC addresses on different VXLAN segments separate, so that they can coexist without duplication issues. ...
0
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1answer
111 views

What application is connecting to a remote site?

I can see with Wireshark that every 5 minutes I have a connection from my computer to ip 165.254.162.243 on udp/8253. This has been going for months. I cannot identify what application or process is ...
3
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1answer
2k views

What's URD in iptables?

I've been playing around with various iptables configurations lately, and I noticed that adding a rule which involves --dport 465 (usually reserved for smtps) results in the human-readable dpt:urd ...
0
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0answers
944 views

raw sockets, iptables and the fact that

iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT DROP So, I just found out that these cute rules don't do s**t when it comes to raw sockets. I know that grabbing a raw socket ...
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0answers
53 views

Installing Unsigned Network Protocol Driver Windows 2012R2

I'm trying to install an unsigned Network protocol driver on a 2012 R2 Windows server installation however the installation just fails the same way unsigned device driver fails. I've already unlock ...
0
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1answer
35 views

Simultaneous http requests planning

A development Meteor app runs in a docker container on aws cloud, it accepts user input and makes HTTP requests to 3rd party websites, parses the data and sends back to the user. Apology; my limited ...
1
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1answer
141 views

Huawei Secospace USG 2000 on a non Default Port

I would like to know which is the default port of IPSec. I have tried to connect on all default ports, but I was unsuccessful. Also, I have applied NMap to them, but have no response.
1
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1answer
3k views

How to capture network packets that use SS7 protocol using Wireshark?

Since SS7 protocol stack is used in GSM mobile telephony network, we can't get the packets of SS7 protocols using Wireshark in Windows Computer and browsing in a web browser like Google chrome. So ...
-1
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1answer
50 views

Does anything changes for a client in the API communication after the command STARTTLS is sent and a response received

I'm trying to understand how the command STARTTLS in IMAP works exactly and what becomes different when it's sent. After I've sent the command "STARTTLS" before login process and received the response ...
0
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1answer
177 views

can tcpdump detect higher level protocols like wireshark?

Wireshark will guess what higher level protocols are being used in a packet, but how can I get tcpdump to do likewise (or any other linux command line tool)? For example, the following screenshot ...
0
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1answer
52 views

Enforce a client hardware address via DHCPv4

Is there a DHCPv4 option that allows a client to tell the server never or at least for some time to deny any other client hardware address than its own? I'm looking for a way to deny any other host ...
0
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1answer
785 views

What's the legit use of a deauthentication packet?

Most people that have tampered with external wireless networks in a malicious fashion for the sake of education (hopefully your own personal testing network) have probably heard of a deauthentication ...
0
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1answer
624 views

Nic teaming server 2012 r2

I've been asked to build a server and team the nics, my understanding is the nics should each be dhcp enabled and the team should be configured with a static ip. Would this be correct and also what ...
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0answers
39 views

SNMP/PJL - used area printed on a page

How can find the effective area printed on a page direct from printer device? I can't access the file stream to do direct on it.
0
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1answer
294 views

How SMTP (receiving emails) works?

I have a very hard time to understand how SMTP works. I've read already: Message Submission for Mail Internet Mail Architecture Internet Message Format Simple Mail Transfer Protocol I know the SMTP ...
2
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1answer
440 views

Why is the DHCP lease start time greater than the end time

On our DHCP server I see this quite a bit on some of our leases and I am not sure why its being reported like this. lease <IP Address> { starts 5 2015/08/21 13:22:20; ends 5 2015/08/21 13:22:...
1
vote
1answer
135 views

MAC Layer Retransmissions during the same TXOP

Back in the day I was messing around with MadWifi and, if I remember properly, after a packet was transmitted if the sender did not receive an ACK in SIFS time after the completion of the transmission,...
25
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1answer
4k views

Under what circumstances is TCP-over-TCP performing significantly worse than TCP alone (2014)?

Many admins keep perpetuating - on ServerFault and elsewhere - how bad of an idea TCP-over-TCP is, e.g. in VPNs. That even the slightest packet loss will make one suffer from at least severe ...
0
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1answer
93 views

Worldwide IP Latency [closed]

I want to create a simulation of the protocol MIPv6 (http://www.ietf.org/rfc/rfc3775.txt), for this reason I need information about latency, jitter and round-trip time. My first guess is install ...
-2
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1answer
715 views

Configure Protocols using iptables log file with ndpi [closed]

I am using iptables with ndpi to filter my network and add two rules to my iptables rules they are iptables -I INPUT -m ndpi --http -j LOG iptables -I INPUT -m ndpi --google -j LOG In my log file I ...
1
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2answers
1k views

What is the KRYPTOLAN protocol?

I've searched for a while and can't seem to find any information on what KRYPTOLAN is. For the transport layer, IP protocol number 0x41 is assigned. In addition, ports 398/udp and 398/tcp are also ...
0
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1answer
121 views

Token Ring Number of nodes in MAU [closed]

why the token ring has limitation of 260 nodes per MAU using STP cables? How the number of nodes per MAU is calculated? I know we can use more than 260, but why IEEE-802.5 is Standardized it to 260 ...
6
votes
1answer
154 views

Tools for detecting network traffic filtering [closed]

In Iran we have an ongoing problem with the govt. blocking and manipulating various network protocols. I'm looking for a tool, framework or platform to help us analyze and report on any of these ...
1
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0answers
40 views

Routing table taking long time to update for adhoc networks and OLSR

I am using OLSR to implement adhoc network and analyse the throughput.I have olsr working on 3 interconnected computers on adhoc network. I am using jperf to simulate and visualise the data ...
0
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1answer
800 views

ow to get protocol signatures?

Does anyone know how can we get signatures for various protocols e.g. BGP, DHCP, VxLAN etc? By signatures, I actually mean the pattern (e.g. something like 0x234557888) used for pattern-matching in a ...
2
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3answers
318 views

Can i set 443 as default web port which means it can only be accessed via https and no port 80

As title says, I want to set my apache to listen on 443, and will configure SSL. So, My Question is :- 1). Does that mean, i will not have port 80 or any other port which is no ssl ? 2). My site ...
0
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2answers
2k views

Source and Destination Packets on Wireshark Relative or Absolute?

New in Packet Analysis. Sniffing on the Ethernet device of my computer. Does the Source and Destination columns on Wireshark tell the source and destination from where the packet was originated and ...
0
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1answer
28 views

How can i go ahead to configure two subnetted networks to apache so as to create two lone networks that are connected via switch?

I want to connect 15 systems to a server so that they do not communicate among themselves directly but do so via server, how should i go ahead? i need to allot say 5 systesm to HR people and 5 other ...
0
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2answers
475 views

Why does ipv6 not specify a protocol version?

I am relatively new to dealing with network packets, but as I look into the ipv6 header formats, I do not see a place where the ipv6 headers define what protocol is used in the data section -- but the ...
9
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2answers
36k views

Why is ICMP categorized as a layer 3 protocol? [closed]

ICMP is categorized as a layer 3 protocol in the OSI model, but as far as i can tell it does not meet the definition of a network layer protocol. It does not provide addressing or packet routing (it ...
0
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1answer
126 views

OSPF LSA Group Pacing

Is LSA group pacing enabled by default in Cisco IOS or something that needs to be configured under the OSPF process? How do you determine if it is currently enabled or not?
-1
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1answer
78 views

Calculation units in EtherType frame field [closed]

The EterType ethernet frame field value is represent a payload field length in bits or bytes?
0
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1answer
152 views

What decides what tunnels inside EAP-TTLS?

If EAP-TTLS is a EAP method that establishes a TLS tunnel, what goes in the tunnel? It could be another EAP method, but it could also be PAP. What decides? The server, the supplicant, or do they ...
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1answer
122 views

Services and protocols to restrict torrent traffic at a university campus [closed]

Which service has the ability of blocking bit-torrent traffic on a subnet network, snmp or bgp? Are these protocols useful for such blocking ?
0
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2answers
3k views

SQL Server Express cannot connect error: 28 - Server doesn't support requested protocol

I cannot connect to my local SQL Server Express (2012, but the version shouldn't matter) from my server (Windows 2008 R2) to use a tool on it (APEX SQL Data Diff if you are wondering). I can browse ...
-1
votes
1answer
248 views

Which protocol do clients use when communicating with servers in a SAN [closed]

I'm trying to wrap my head around how a SAN works and how it is implemented. If I understand this well, clients wanting to access the storage devices in a SAN need to communicate with the servers via ...
0
votes
1answer
764 views

Installing VPN servers that support PPTP, L2TP and openVPN protocols [closed]

Looking for VPN Server that support PPTP, L2TP and OpenVPN Protocols, also these servers must use the same data base so each account created on any of these servers must work across all the other ...
1
vote
1answer
51 views

Bug in CDP implementation

We are developing a Linux based ethernet switch which has 6 ports. We are done with CDP protocol. I have connected a Cisco device to port 2. When I quiery for the Cisco device, I get the reply and ...
16
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2answers
32k views

IIS 7.5 Globe with Question Mark Icon

I changed the Physical Path to my website in IIS 7.5 and the icon changed to this: It was completely vanilla before I changed that. I can't find any documentation on what that icon means and the ...
0
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1answer
1k views

Capturing network traffic (rtmp) between VMs or using loopback in the same VM using wireshark

I need to to capture RTMP traffic between two virtual machines (server and client) or atleast have the server and client on the same machine and capture the traffic. I am able to capture the traffic ...
10
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3answers
20k views

How to find all the snmp enabled devices in my network?

I want to find all the snmp enabled devices in my network, I got something like how it works in a agent and manager architecture. I got net-snmp library to create a simple application to get the snmp ...
4
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3answers
3k views

identify a router that cuts certain port

Is there a way to identify which particular router between me and some server blocks connections on certain port? I am in a hotel in Thailand, where they have recently changed some settings in their ...
1
vote
1answer
756 views

What was SPX from the IPX/SPX stack ever used for? [closed]

Been trying to learn about older networking protocols a bit, and figured that I would start with IPX/SPX. So I built two MS-DOS virtual machines in VirtualBox, and got IPX communications working (...
2
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3answers
601 views

Designing a persistent asynchronous TCP protocol

I have got a collection of web sites that need to send time-sensitive messages to host machines all over my metro area, each on its own generally dynamic IP. Until now, I have been doing this the way ...