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Groups > comp.lang.java.programmer > #34559
| From | Arne Vajhøj <arne@vajhoej.dk> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Picking an unused port number |
| Date | 2016-06-07 21:53 -0400 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <nj7tr3$s9b$1@gioia.aioe.org> (permalink) |
| References | (4 earlier) <nj55ri$get$1@jstuckle.eternal-september.org> <nj57vc$i9u$1@gioia.aioe.org> <nj58v1$n7t$1@jstuckle.eternal-september.org> <nj5dp0$o7d$1@gioia.aioe.org> <nj6jed$llc$1@jstuckle.eternal-september.org> |
On 6/7/2016 9:50 AM, Jerry Stuckle wrote:
> On 6/6/2016 11:07 PM, Arne Vajhøj wrote:
>> On 6/6/2016 9:45 PM, Jerry Stuckle wrote:
>>> On 6/6/2016 9:28 PM, Arne Vajhøj wrote:
>>>> On 6/6/2016 8:52 PM, Jerry Stuckle wrote:
>>>>> On 6/6/2016 6:44 PM, Wayne wrote:
>>>>>> On 6/4/2016 8:50 PM, Jerry Stuckle wrote:
>>>>>>> On 6/4/2016 11:24 AM, nathanturner369@gmail.com wrote:
>>>>>>>>> So, in general, is there any rule you should use when selecting a
>>>>>>>>> port
>>>>>>>>> number, other than picking one > 1024?
>>>>>>>>
>>>>>>>
>>>>>>> Make it configurable, and > 4095, not 1024.
>>>>>>
>>>>>> Why?
>>>>>>
>>>>>
>>>>> Ports 0-4095 are reserved.
>>>>
>>>> ????
>>>>
>>>> 0-1023 are system ports
>>>> 1024-49151 are registered ports
>>>> 49152–65535 are ephemeral ports
>>>>
>>>> 80XX port numbers are very frequently used in the Java world.
>>>>
>>
>>> If 1024-49151 are registered ports, then why would 80xx ports be used in
>>> the Java world?
>>
>> Many possible reasons:
>> - they may have been assigned to the Java purpose
>> - they may have been assigned to a general purpose that is compatible
>> with Java usage
>> - they may not have been assigned yet
>>
>
> "May" does not work. Which is it?
Most likely all of them.
Many ports - many reasons.
>>> 0-4095 are generally considered "reserved" by commonly used protocols.
>>> Others are used by other protocols, but not generally considered "in
>>> use".
>>
>> That is not how IANA looks at it.
>
> Whatever. You're the expert on EVERYTHING. Trolls always are.
One does not need to be an expert to know about IANA and RFC 6335.
Nor to understand RFC 6335 about pot number ranges:
<quote>
6. Port Number Ranges
TCP, UDP, UDP-Lite, SCTP, and DCCP use 16-bit namespaces for their
port number registries. The port registries for all of these
transport protocols are subdivided into three ranges of numbers
[RFC1340], and Section 8.1.2 describes the IANA procedures for each
range in detail:
o the System Ports, also known as the Well Known Ports, from 0-1023
(assigned by IANA)
o the User Ports, also known as the Registered Ports, from 1024-
49151 (assigned by IANA)
o the Dynamic Ports, also known as the Private or Ephemeral Ports,
from 49152-65535 (never assigned)
Of the assignable port ranges (System Ports and User Ports, i.e.,
port numbers 0-49151), individual port numbers are in one of three
states at any given time:
o Assigned: Assigned port numbers are currently assigned to the
service indicated in the registry.
o Unassigned: Unassigned port numbers are currently available for
assignment upon request, as per the procedures outlined in this
document.
o Reserved: Reserved port numbers are not available for regular
assignment; they are "assigned to IANA" for special purposes.
Reserved port numbers include values at the edges of each range,
e.g., 0, 1023, 1024, etc., which may be used to extend these
ranges or the overall port number space in the future.
In order to keep the size of the registry manageable, IANA typically
only records the Assigned and Reserved service names and port numbers
in the registry. Unassigned values are typically not explicitly
listed. (There are very many Unassigned service names and
enumerating them all would not be practical.)
As a data point, when this document was written, approximately 76% of
the TCP and UDP System Ports were assigned, and approximately 9% of
the User Ports were assigned. (As noted, Dynamic Ports are never
assigned.)
</quote>
Arne
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Re: Picking an unused port number nathanturner369@gmail.com - 2016-06-04 08:24 -0700
Re: Picking an unused port number Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-06-04 09:56 -0700
Re: Picking an unused port number Eric Douglas <e.d.programmer@gmail.com> - 2016-06-06 05:28 -0700
Re: Picking an unused port number Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-06-06 15:40 -0700
Re: Picking an unused port number Nigel Wade <nmw@ion.le.ac.uk> - 2016-06-07 09:43 +0100
Re: Picking an unused port number Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-06-07 07:43 -0700
Re: Picking an unused port number Nigel Wade <nmw@ion.le.ac.uk> - 2016-06-07 17:28 +0100
Re: Picking an unused port number Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-06-07 09:40 -0700
Re: Picking an unused port number Nigel Wade <nmw@ion.le.ac.uk> - 2016-06-08 10:32 +0100
Re: Picking an unused port number Eric Douglas <e.d.programmer@gmail.com> - 2016-06-08 06:45 -0700
Re: Picking an unused port number Nigel Wade <nmw@ion.le.ac.uk> - 2016-06-08 15:06 +0100
Re: Picking an unused port number Eric Douglas <e.d.programmer@gmail.com> - 2016-06-08 07:36 -0700
Re: Picking an unused port number Martin Gregorie <martin@address-in-sig.invalid> - 2016-06-08 18:03 +0000
Re: Picking an unused port number Jerry Stuckle <jstucklex@attglobal.net> - 2016-06-04 20:50 -0400
Re: Picking an unused port number Wayne <wayne@nospam.invalid> - 2016-06-06 18:44 -0400
Re: Picking an unused port number Jerry Stuckle <jstucklex@attglobal.net> - 2016-06-06 20:52 -0400
Re: Picking an unused port number Arne Vajhøj <arne@vajhoej.dk> - 2016-06-06 21:28 -0400
Re: Picking an unused port number Jerry Stuckle <jstucklex@attglobal.net> - 2016-06-06 21:45 -0400
Re: Picking an unused port number Arne Vajhøj <arne@vajhoej.dk> - 2016-06-06 23:07 -0400
Re: Picking an unused port number Jerry Stuckle <jstucklex@attglobal.net> - 2016-06-07 09:50 -0400
Re: Picking an unused port number Lew <lewbloch@gmail.com> - 2016-06-07 13:46 -0700
Re: Picking an unused port number Jerry Stuckle <jstucklex@attglobal.net> - 2016-06-07 19:31 -0400
Re: Picking an unused port number Lew <lewbloch@gmail.com> - 2016-06-07 17:26 -0700
Re: Picking an unused port number Jerry Stuckle <jstucklex@attglobal.net> - 2016-06-07 21:34 -0400
Re: Picking an unused port number Lew <lewbloch@gmail.com> - 2016-06-08 13:52 -0700
Re: Picking an unused port number Jerry Stuckle <jstucklex@attglobal.net> - 2016-06-08 17:49 -0400
Re: Picking an unused port number Arne Vajhøj <arne@vajhoej.dk> - 2016-06-07 21:53 -0400
Re: Picking an unused port number a.laforgia@gmail.com - 2016-06-07 00:11 -0700
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