TCP and IP are two important protocols used in networking today. Due to their importance, the Internet Protocol Suite is also commonly known as "TCP/IP"
Questions tagged [tcpip]
455 questions
472
votes
8 answers
How does IPv4 Subnetting Work?
This is a Canonical Question about IPv4 Subnets.
Related:
How does IPv6 subnetting work and how does it differ from IPv4 subnetting?
How does Subnetting Work, and How do you do it by hand or in your head? Can someone explain both conceptually…
Kyle Brandt
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136
votes
7 answers
In Windows, using the command line, how do you check if a remote port is open?
What is a simple way in Windows to test if traffic gets through to a specific port on a remote machine?
Matt
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102
votes
6 answers
Is X.Y.Z.0 a valid IP address?
Are IP addresses with a 0 in the last octet valid?
10.6.43.0
In my case, I have the the following netmask
255.255.252.0
What about a 0 for the other octets?
Alan H
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92
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3 answers
What is the maximum port number?
I'd like to set some linux services to non-standard ports - what's the highest valid port number?
Yehosef
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62
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14 answers
Why would you use IPv6 internally?
Of course, I realize the need to go to IPv6 out on the open Internet since we are running out of addresses, but I really don't understand why there is any need to use it on an internal network. I have done zero with IPv6, so I also wonder: Won't…
KCotreau
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51
votes
3 answers
Unix socket vs TCP/IP host:port
Could someone please describe to me the pros and cons of using a Unix socket file vs a tcp/ip localhost:port when setting up services on a server (Ubuntu, FWIW)?
In this particular instance it's for a Python WSGI server (uWSGI) but I'm just…
Ludo
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48
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11 answers
What is the difference between UDP and TCP?
My router has two protocols (and a "both" option) that I can select when setting up port forwarding: UDP and TCP. What is the difference between these two protocols and when would you select one over the other in port forwarding?
Guy
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41
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13 answers
How to get a list of all IP addresses (and ideally device names) on a LAN?
Our network gave an error that there was an IP address conflict and I'd like to find what all the device IP addresses are. (I've also had need of that before). (update/clarification:I'm looking for a Windows-based too.)
Any suggestions?
I've read…
Clay Nichols
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37
votes
8 answers
When/why to start subnetting a network?
Under what conditions does one start to consider subnetting a network?
I'm looking for a few general rules of thumb, or triggers based on measurable metrics that make subnetting something that should be considered.
Adam Davis
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35
votes
6 answers
Huge amount of TIME_WAIT connections says netstat
Okay, this is creeping me out - I see about 1500-2500 of these:
root@wherever:# netstat
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 localhost:60930 localhost:sunrpc TIME_WAIT …
KTamas
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35
votes
4 answers
What does a DNS request look like?
I have seen what the text representation of an HTTP request is, but what does a DNS request look like? Where in the data is the location of the URL you are trying to locate? Also, how is the response formatted?
AMWJ
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34
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4 answers
Which is the default TCP connect timeout in Windows?
Which is the default TCP connect timeout in Windows? There is a registry key to configure it or it's set dynamically?
Renan Vinícius Mozone
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33
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2 answers
How to set the preferred network interface in linux
I have my network set up like this.
http://docs.google.com/Doc?docid=0AZ1YxuLE4djaZGhqN2s1NmRfMjhjNjc0Ym1meg&hl=en
In words: I have a machine (Calcium, running Arch Linux) that has two network interfaces. eth0 is hoooked up to a router, and is…
Mike Cooper
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33
votes
3 answers
Tuning Linux IP routing parameters -- secret_interval and tcp_mem
We had a little failover problem with one of our HAProxy VMs today. When we dug into it, we found this:
Jan 26 07:41:45 haproxy2 kernel: [226818.070059] __ratelimit: 10 callbacks suppressed
Jan 26 07:41:45 haproxy2 kernel: [226818.070064] Out of…
Jeff Atwood
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24
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192.168.1.x more exploitable?
Our IT services firm is proposing a network reconfiguration to use the IP range 10.10.150.1 – 10.10.150.254 internally as they state the current IP scheme using manufacturer defaults of 192.168.1.x is "making it to easy to exploit".
Is this true?…
Michael Glenn
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