Questions tagged [network-protocols]
The network-protocols tag has no usage guidance.
103
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31
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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 ...
21
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5
answers
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If e-mail is only "best effort" delivery, is there a similar protocol with guaranteed delivery?
It's often established in law that faxes are accepted documents because their delivery is 'guaranteed', whereas e-mail is not because its delivery is not. Isn't this just begging for a TCP-based ...
21
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6
answers
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How is the MTU is 65535 in UDP but ethernet does not allow frame size more than 1500 bytes
I am using a fast ethernet of 100 Mbps, whose frame size is less than 1500 bytes (1472 bytes for payload as per my textbook). In that, I was able to send and receive a UDP packet of message size 65507 ...
18
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3
answers
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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 ...
15
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2
answers
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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 ...
12
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2
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What's the protocol-level difference between IPSec and "Cisco IPSec"?
Most VPN clients distinguish between IPSec and "Cisco IPSec." For example, (Apple's) iOS treats them as essentially separate things.
But I can't find any explanation of what the protocol-level ...
11
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5
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Understand IP addresses and location
I risk posing an ill formed question here, but I'll give it a whirl.
Does it generally stand to reason that the nearer IP address A is to IP address B numerically, then the nearer IP address A is ...
11
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3
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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 ...
6
votes
1
answer
326
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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 ...
5
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2
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ICMP Reliability
Let's say someone sends a UDP packet, just like a traceroute implementations. The packet has a TTL of 1 in the IP header, causing the first router to discard it and generate an ICMP Time Exceeded ...
5
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3
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3k
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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 ...
5
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1
answer
4k
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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 ...
4
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3
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3k
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Is the Matrix protocol Fediverse?
The title says it all. Reading about the Fediverse, the Matrix protocol seems to fit its characteristics, however I found no reference of that anywhere.
4
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1
answer
365
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How do IP address to location services gather their information
My continued series of questions on IP addresses (ref Q1 and Q2).
There are several IP address to location services. For instance: http://www.ip-adress.com/ip_tracer/ and http://www.ip2location.com/...
4
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1
answer
3k
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How are IP addresses assigned? What do the parts mean? [duplicate]
Possible Duplicate:
How does Subnetting Work?
IP addresses and geographical locations
How does my IP address get assigned to me? Is there any ordering? For instance by time or by location or by ...
3
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4
answers
4k
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Ethernet switch capacity question
We're looking at hooking up 48 small embedded systems with 10/100 Ethernet ports to an Ethernet switch and then have that switch talk to a server upstream via a faster connection. I have a couple of ...
3
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2
answers
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How are CIFS and SMB related to each other?
Are they synonyms, or components of a protocol stack?
Answers with proof links are welcome.
3
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2
answers
515
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SCTP stability and performance? [closed]
Anyone out there using SCTP? Especially on Solaris and Linux? What are your experiences - is it ready for production?
3
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3
answers
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Why PTP uses Sync-followup pairs?
The PTP (Precision Time Protocol), uses Sync message then Follow-up message, as described in the article "Understanding the IEEE 1588 Precision Time Protocol".
I don't understand why do we need ...
3
votes
1
answer
1k
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Confusion about TCP packet analysis terms
I'm analyzing our network and have some confusion about the terms:
this is the 2-packet output from source to destination.
from these i have to get some features as describe, pls make me clear...
...
3
votes
2
answers
94
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"entering link in browser" to "finding route to host" how it works?
Is there a wiki or book, which explains what happens when user enters a link in the browser, and how the dns is resolved, how the router finds the route to the host etc.. I am mainly interested in ...
2
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3
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1k
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Ethernet: network topology
Consider a standard GigE network switch. In order to do the switching, presumably it needs to maintain a map of MAC addresses of all things that exist on the network to its (switch's) port numbers.
...
2
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3
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What are the most common protocols on the internet? [closed]
For 69 views in the first day, 2 up-votes within 2 days, it's a shame that this was closed.
What are the commonly used protocols that sit atop TCP/IP and UDP/IP?
My list includes HTTP and BitTorrent....
2
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3
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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 ...
2
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2
answers
3k
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Ports that are always open? How does softwares like bittorrent manage to communicate even without port forwarding?
How come bittorrent clients manage to communicate to servers and other peers even if the user has not configured port forwarding on their routers?
Of course the speed will be reduced compared to ...
2
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3
answers
673
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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 ...
2
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2
answers
2k
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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 ...
2
votes
1
answer
3k
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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 ...
2
votes
1
answer
842
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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:...
2
votes
1
answer
747
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hping command line assistance
hping has such horrible documentation and seemingly many different types of syntaxes.
I would like to know what the hping command would be to send a TCP packet with a source IP of 192.168.0.2, a ...
2
votes
2
answers
383
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What is the point of PPPoE? [closed]
I am trying to expand my knowledge of networking beyond the basics. I have started reading about PPP, and how it is used in DSL modems with PPPoE and PPPoA.
My first impression of PPP was "well that ...
1
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2
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482
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(Simple) UDP Protocol - Networking
I know that UDP is an unreliable protocol where things can arrive out of order, fail to arrive completely, etc.
I'm also aware that when using UDP for something like traceroute, packets that arrive ...
1
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2
answers
307
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how do I block a LAMP server from any communication with outside except a whitelist!
Hi I want to black my server from any contact with a black list of ips and I would also like to block any domain names if possible, and have it only send http headers back and forth between ip ...
1
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1
answer
366
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Host ::1 resolves to remote IP
/etc/hosts files usually have this line, ::1 localhost. I thought ::1 was the equivalent of 127.0.0.1/localhost, and from my reading it seems to be the IPv6 version. So I was using it in Apache for ...
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1
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Nginx HTTP/SPDY over SCTP
I've ready a thread in russian Nginx maillist about implementing HTTP/SPDY over SCTP in future.
I realize that SCTP is completely unusable for public service at the moment, but what changes should ...
1
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1
answer
391
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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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2
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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 ...
1
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1
answer
1k
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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 (...
1
vote
1
answer
209
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Remote desktop protocol implementation
I'm trying to find the best network solution for my own remote desktop application only for Windows (XP above) and I have the following requirements:
First of all, the application should work, let's ...
1
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2
answers
2k
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Does intra-subnet traffic on a WLAN pass through a router?
Lets say I have two hosts, 1 and 2, both connected to the same wireless router, same network and same subnet.
If 1 pings 2 will:
(a) 1 addresses a wireless packet to the router's MAC address, but ...
1
vote
1
answer
38
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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?
...
1
vote
1
answer
274
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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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1
answer
4k
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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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1
answer
335
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How to get UCARP to work over wireless?
I would like to get ucarp to work over a wireless (802.11g) interface, but the packages is never seen on the wired end.
The setup looks like this: Box1 (10.0.0.11, wireless) -- AP -- (10.0.0.13, ...
1
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1
answer
466
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The iptables problem with NAT under Ubuntu
Greet Everybody
I have some problems about iptables rules under Ubuntu .
I create a simple firewall with the function of NAT,then restart the server.
the command to create:
iptables -F
iptables -P ...
1
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0
answers
239
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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.
...
1
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0
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68
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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.
1
vote
1
answer
156
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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,...
1
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0
answers
49
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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 ...
1
vote
1
answer
59
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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 ...