pop 110/995, imap 143/993 ?

[Gedalya]

On 08/21/2017 06:04 PM, Sebastian Arcus wrote:
>
> On 21/08/17 10:37, Gedalya wrote:
>> On 08/21/2017 07:28 AM, voytek at sbt.net.au wrote:
>>> is there a 'preferred way'?  should I tell users to use 143 over 993 ? or
>>> 993 over 143? or?
>> There is no concrete answer. There are various opinions and feelings about this.
>> The opinion againt 993/995 is that these are not standard ports, 
>
> Out of curiosity, is there a source for this? It's the first time I hear that 993/995 are not standard ports - and searching on the Internet, I can't find any evidence to back it up? Also, pretty much all email software has been using them for the past 20 years or so. It seems like a curiously high rate of adoption for a non-standard :-)

What kind of evidence would support a negative? I don't understand.

Evidence could demonstrate that something is indeed a standard.
"Standard" and common practice are not the same thing. A "Standrd" is a document that describes what practice ought to look like.
C has a (series of) standard(s), Perl 5 is not exactly standardized. It's just implemented and documented.

Either way, at this point these ports are indeed listed here:

https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt

So perhaps it can be said that those still arguing against it on the basis of it being "non-standrd" are still arguing against officially assigning these port numbers, because the old ports are perfectly good, even after the assignment has already been listed by IANA.