Tag Info

Hot answers tagged

47

Due to the way TCP/IP works, connections can not be closed immediately. Packets may arrive out of order or be retransmitted after the connection has been closed. CLOSE_WAIT indicates that the remote endpoint (other side of the connection) has closed the connection. TIME_WAIT indicates that local endpoint (this side) has closed the connection. The ...


47

It's not MS it is the ISOC ;-) Have a look at reserved IP address RFC 5735 under special use IPv4: here 169.254.0.0/16 - This is the "link local" block. As described in [RFC3927], it is allocated for communication between hosts on a single link. Hosts obtain these addresses by auto-configuration, such as when a DHCP server cannot be ...


46

Because www.google.com is a lot easier to remember than 64.233.169.147? It also adds transparency to a services location. You can move both geographically and between IP blocks and the rest of the world doesn't have to be notified of that change to continue using your service.


41

The short answer An Internet spec called RFC 1918 reserved a few blocks of addresses for "private" networks, which is what you should use when you don't have enough public, routable IP addresses to go around. 192.168/16 was one of those blocks. The long answer (and then some) Back in the good old days, everything on the Internet got its own public, ...


38

The use of 169.x.x.x addresses are defined within a standard colloquially known as APIPA - Automatic Private IP Addressing. In a nutshell, if a network device has not been assigned a fixed (static) address and cannot obtain one by asking (DHCP), the device says to itself, "Well, I'd better make up an address of my own so I can communicate on this network", ...


34

Although everybody else suggests that DNS is not necessary for the internet to work, I disagree. DNS is not necessary for an IP based network to work but for the Internet as we know it today it is absolutely necessary!!


33

Yes, there is a benefit to using IPv6 at home. The main one is education, i.e. you will gain experience at administering an IPv6 network that you can put on your resume. In about two years from now, sometime in 2011, the world will run out of IPv4 addresses and there will be a surge in demand for IPv6 networking, and that includes a demand for people ...


24

A port isn't open if something isn't listening for a connection on it. The reason it is bad form to have all ports open to everywhere is that it exposes those services that are listening on those ports to exploits. That is why firewalls exist, to limit what is allowed to connect to certain ports, to reduce the surface area exposed by services. EDIT To ...


24

If you are on a Windows machine, open a command box (Start...run...cmd), PING the target machine so you have made contact with it and then issue the command arp -a to view your local arp table, which will list IP addresses and their corresponding MAC addresses eg: C:\Users\L3K>arp -a Interface: 192.168.200.128 --- 0xb Internet Address Physical ...


23

For Windows 7, Windows Vista and Windows XP, the MTU for various interfaces is available from Windows itself using netsh. Windows 7, Windows Vista To show current MTU on Windows 7 or Windows Vista, from a command prompt: C:\Users\Ian>netsh interface ipv6 show subinterfaces MTU MediaSenseState Bytes In Bytes Out Interface ---------- ...


16

In IPv4: Nope. They will see the MAC of the device which forwarded the packet to the server, likely their border router. In IPv6, the 64 bit "host" part of the full 128 bit address is often automatically generated from the MAC address, and hence might be visible to the server one connects to. See also How to avoid exposing my MAC address when using IPv6?


14

The TCP connection limit is not enforced, but it may be bound by legal agreement to not permit more than 10 clients. See this from Microsoft: Inbound connections limit in Windows XP In a command prompt type: net config server This shows max allowed logged on users, and max open files per session


13

I use it to be able to reach all my machines from outside without doing anything special. You could also use the improved multicast support to stream data in a much more efficient way. IPv6 also removes a checksum so you could perhaps notice a small improvement in performance, but most likely not. I try to use IPv6 whenever possible, mostly because it's a ...


12

The TCP protocol guarantees accurate delivery regardless of underlying mechanisms. There is no guarantee that every protocol that it might run over will do any sort of integrity checking. SLIP, for example, has no error detection.


12

You may be thinking of number of ports. There are 65536 ports available in the TCP in the current versions of IPv4. This is not just a Linux limitation, its part of the protocol. Your IP address identifies your machine, and the port identifies a program on your machine. But, the number of connections isn't limited by that. A connection consists of 5 ...


11

It is a private block of IPs that aren't allowed to be routed on the public Internet and are reserved for internal use to be NATed to the outside world. The document that defines this is RFC 1918, which is enforced by IANA. The blocks of private-use IPv4 addresses are: 10.0.0.0 /8 (any address beginning with 10.x.x.x) 192.168.0.0 /16 (any address ...


10

Check out TCPView, which is a GUI to do this stuff: http://technet.microsoft.com/en-us/sysinternals/bb897437.aspx


10

Skynet is a rootkit, not good. It is difficult to detect and remove. Download and run Stubware http://www.thestubware.com/malware_removal/skynet/ After you have rebooted to remove the skynet driver with Stubware, download and run MBAM, do a full system scan, when it is done scanning, allow it to remove anything it finds. 2 . Download, install and Update ...


10

netsh winsock reset c:\winsock.log netsh int ip reset c:\ipreset.log That being said, your best bet is to flatten the computer and reinstall. You never know what else might be lurking around.


10

You may enable packet forwarding by entering sudo sysctl -w net.inet.ip.forwarding=1 into the Terminal.


10

One word: Netcat Netcat is the go-to tool for this sort of thing. You can thrash whatever port you choose with udp packets with something like: nc -u host.example.com 53 << /dev/random (53 is your port number) Or you can send an actual file, or tell it to bind that port and listen as a service, or whatever you like.


10

Translation from a string to an address is usually performed by the POSIX function getaddrinfo(). This function first checks for a numeric IP address using inet_addr(), and if that fails it will then attempt to resolve the string as a domain name. inet_addr() interprets numbers with a leading 0 as octal, so for example 010 would become 8, and 019 would be ...


10

If I register a domain name with godaddy and don't like godaddy anymore I can go to another provider and keep my domain name. The same thing isn't possible with IP addresses as IP addresses are alocated to specific companies and are nothing that you can take with you.


9

One easy way to edit the hosts file is using the freeware Windows program HostsMan. HostsMan is a freeware application that lets you manage your Hosts file with ease In Vista / Windows 7 it needs to run with administrative privileges, but it doesn't require going into safe mode.


9

Basically the "WAIT" states mean that one side closed the connection but the final confirmation of the close is pending. See e.g. this diagram of TCP states for details: http://www.jxos.org/Projects/TCP/tcpstate.html


9

To state Dave M's answer in another terms, your DHCP server has a problem and cannot allocate an IP address. When Windows and any other OS is configured to get an IP via DHCP and they don't get any, they automatically assign 169.254.xxx.xxx IP


9

The Windows Sysinternals Suite contains a tool called TcpView. TcpView will show you all of the connections on your machine similar to netstat. It will also allow you to close the connection or kill the process hosting the connection.


8

First, what you say is not factually correct: Linux up to kernel version 2.6.18 uses BIC by default. Linux kernel 2.6.19 and later uses CUBIC by default. Linux's TCP congestion control mechanisms are pluggable, e.g. you can change them on the fily. Windows XP and earlier uses TCP Reno (or New Reno) Windows Vista and later also has Compound TCP, which is ...



Only top voted, non community-wiki answers of a minimum length are eligible