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Emin.shopper Martinian.shopper wrote:

> Is there a good way to choose/assign random dynamic port numbers in python?
>
> I had in mind something like the following, but if multiple programs are
> generating random port numbers, is there a way to check if a given port
> number is already taken?
>
> def GenerateDynamicPortNumber():
> "Generate a random dynamic port number and return it."
> # port numbers between 49152 to 65535 are dynamic port numbers
> return 49152 + random.randrange(15000)

def GenerateDynamicPortNumber():
return 0

(to get the actual number, use getsockname() on the socket after you've
called "bind" on it)

</F>

On 3 Gen, 23:21, Fredrik Lundh <fred...@pythonware.com> wrote:
> Emin.shopper Martinian.shopper wrote:
> > Is there a good way to choose/assign random dynamic port numbers in python?
>
> > I had in mind something like the following, but if multiple programs are
> > generating random port numbers, is there a way to check if a given port
> > number is already taken?
>
> > * * def GenerateDynamicPortNumber():
> > * * * * "Generate a random dynamic port number and return it."
> > * * * * # port numbers between 49152 to 65535 are dynamic port numbers
> > * * * * return 49152 + random.randrange(15000)
>
> * * def GenerateDynamicPortNumber():
> * * * * return 0
>
> (to get the actual number, use getsockname() on the socket after you've
> called "bind" on it)
>
> </F>

By using 0 as port number value you let kernel choose a free
unprivileged random port:

>>> import socket
>>> s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
>>> s.bind(('', 0))
>>> s.getsockname()
('0.0.0.0', 3070)

On 2008-01-04, Giampaolo Rodola' <> wrote:

>> * * def GenerateDynamicPortNumber():
>> * * * * return 0
>>
>> (to get the actual number, use getsockname() on the socket after you've
>> called "bind" on it)
>>
>> </F>
>
> By using 0 as port number value you let kernel choose a free
> unprivileged random port:

The port number chosen isn't random on many OSes. If the OP
really wants a random port number, he'll have to generate it
himself.

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