How do ports work with IPv6?

Question

Conventional IPv4 dotted quad notation separates the address from the port with a colon, as in this example of a webserver on the loopback interface:

127.0.0.1:80

but with IPv6 notation the address itself can contain colons. For example, this is the short form of the loopback address:

::1

How are ports (or their functional equivalent) expressed in a textual representation of an IPv6 address/port endpoint?

Answer 1

They work almost the same as today. However, be sure you include [] around your IP.

For example : http://[1fff:0:a88:85a3::ac1f]:8001/index.html

Wikipedia has a pretty good article about IPv6: http://en.wikipedia.org/wiki/IPv6#Addressing

Answer 2

The protocols used in IPv6 are the same as the protocols in IPv4. The only thing that changed between the two versions is the addressing scheme, DHCP [DHCPv6] and ICMP [ICMPv6]. So basically, anything TCP/UDP related, including the port range (0-65535) remains unchanged.

Edit: Port 0 is a reserved port in TCP but it does exist. See RFC793

Answer 3

They're the same, aren't they? Now I'm losing confidence in myself but I really thought IPv6 was just an addressing change. TCP and UDP are still addressed as they are under IPv4.

Answer 4

I'm pretty certain that ports only have a part in tcp and udp. So it's exactly the same even if you use a new IP protocol

Answer 5

Wikipedia points out that the syntax of an IPv6 address includes colons and has a short form preventing fixed-length parsing, and therefore you have to delimit the address portion with []. This completely avoids the odd parsing errors.

(Taken from an edit Peter Wone made to the original question.)

Answer 6

I would say the best reference is Format for Literal IPv6 Addresses in URL's where usage of [] is defined.

Also, if it is for programming and code, specifically Java, I would suggest this readsClass for Inet6Address java/net/URL definition where usage of Inet4 address in Inet6 connotation and other cases are presented in details. For my case, IPv4-mapped address Of the form::ffff:w.x.y.z, for IPv6 address is used to represent an IPv4 address also solved my problem. It allows the native program to use the same address data structure and also the same socket when communicating with both IPv4 and IPv6 nodes. This is the case on Amazon cloud Linux boxes default setup.