[Python-Dev] PEP 3144: IP Address Manipulation Library for the Python Standard Library

Eric Smith eric at trueblade.com
Wed Aug 19 23:13:05 CEST 2009

> So it sounds like doing what I suggested earlier (default to [-1], allow 
> for customization) is actually required by the RFC :-).  Although it 
> does sound like the RFC only requires that you be able to customize to 
> [0] rather than [-1], rather than any address.  In practical terms 
> though I believe it is possible to do as Tino suggests and configure any 
> crazy address you want to be the broadcast address (or addresses, even) 
> for a network.

If you're doing this, are you really going to be specifying the 
broadcast address as something like network.use_broadcast_index(-2) (or 
even 0) and then using network.broadcast somewhere else? I just don't 
see that happening.

>     I think setting the broadcast address to something else just does
>     not need to be supported.

I agree.

> It is unusual, but frankly, needing to actually do operations on 
> broadcast addresses at all is also a pretty unusual task.  Broadcast 
> itself is a somewhat obscure corner of networking.  I suspect that in 
> many deployments that need to write significant code to deal with 
> broadcast addresses, rather than the usual default stuff, funky 
> configurations will actually be quite common.

I use .broadcast from IPy, and I'm not doing anything funky. All of my 
broadcast addresses are network[-1].

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