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Questions tagged [network-protocols]

103 questions
29
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2 answers

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 throughput degradation if not TCP meltdown, and that…
Nils Toedtmann
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21
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5 answers

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 protocol that guarantees delivery to the same degree…
Jez
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21
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6 answers

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 bytes, which means the packet size was 65507 +…
nikku
18
votes
3 answers

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 tooltip only says "Default Web Site (Multiple…
Chiramisu
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15
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2 answers

Why is ICMP categorized as a layer 3 protocol?

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 uses IP for this), so all it does is send…
Robbie Mckennie
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12
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2 answers

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 differences are. They may be minor, but there definitely…
Dave Peck
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11
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3 answers

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 data from a remote device.I have to write a…
pradiptart
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11
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5 answers

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 to IP address B geographically? Whatever your…
John Berryman
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6
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1 answer

Tools for detecting network traffic filtering

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 activities. If the framework would let us write custom…
Iman
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5
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1 answer

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 showing up when listing rules with iptables -L. I've…
Jules
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5
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3 answers

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 equipment, and now I cannot reach any of my…
Sergiks
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5
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2 answers

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 reply to the sender. Does the router have any…
John Humphreys
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4
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1 answer

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/demo.aspx . How do they collect their data? (i.e.…
John Berryman
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4
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1 answer

How are IP addresses assigned? What do the parts mean?

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 queue? Who divvies up the IP addresses at each…
John Berryman
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3
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2 answers

How are CIFS and SMB related to each other?

Are they synonyms, or components of a protocol stack? Answers with proof links are welcome.
yrk
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