Jon Parise's Blog

Password Composer for iPhone

Sat, 21 Nov 2009 21:17:23 -0800

I often use Password Composer (written by Johannes la Poutré) to generate
unique, per-site passwords. It does an excellent job because it's simple,
unobtrusive, and reliable. The one downside is that you need to have it
available in order to (re)generate the password for a given web site, and that
isn't always convenient, despite the large number of existing Password
Composer implementations.

The main place I find myself missing Password Composer is on my iPhone. Theonly current solution...

posted by Jon Parise on November, 21

Twisted Python and Bonjour

Thu, 19 Nov 2009 20:47:06 -0800

Bonjour (formerly Rendezvous) is Apple's service discovery protocol. It
operates over local networks via multicast DNS. Server processes announce
their availability by broadcasting service records and their associated ports.
Clients browse the network in search of specific service types, potentially
connecting to the service on the advertised port using the appropriate network
protocol for that service.

A common example of Bonjour in action is iTunes' music library sharingfeature. iTunes shari

posted by Jon Parise on November, 19

Classless in-addr.arpa. Delegation

Sun, 15 Nov 2009 18:12:53 -0800

Classless in-addr.arpa. delegation allows network administrators to provide
authoritative reverse DNS on subnets that don't fall on octet boundaries.
This is especially useful for subnets comprised of less than eight bits in the
host portion of the address (i.e. smaller than a class C).

There are two important things to remember: first, we're dealing withclassless subnets, meaning they don't align themselves neatly with IPv4'soctet boundaries (like a class A, B, C, D, or E network); and second, o

posted by Jon Parise on November, 15

Virtual Ethernet Tunneling

Sun, 15 Nov 2009 18:16:14 -0800

This paper discusses the implementation of virtual Ethernet tunnels using
OpenBSD. The current release of OpenBSD at the time of writing (2001) was
version 2.9, so some of the material may be fairly dated. I haven't revisited
the details since then.

Overview

Without going too deep into the technical details, a virtual Ethernet tunnel
uses packet encapsulation, Ethernet bridging, and IPSec encryption to
tunnel a subnet from one host to another host over a public network
(generally, the Internet).

posted by Jon Parise on November, 15

Vim Color Schemes

Sun, 15 Nov 2009 18:07:24 -0800

The Vim text editor supports highly-configurable color schemes which build
upon the editor's rich syntax highlighting system. The stock Vim distribution
includes a number of color schemes, and many more are available from the Vim
Scripts repository.

Color scheme definitions are simply normal Vim scripts that live in the
colors/ directory of the Vim runtime hierarchy (see :help runtimepath).

Color schemes are loaded using the :colorscheme command. The scheme'sname is determined by the filename of

posted by Jon Parise on November, 15

Reloading Python Modules

Tue, 27 Oct 2009 17:20:13 -0700

Being able to reload code modules is one of the many nice features of Python.
This allows developers to modify parts of a Python application while the
interpreter is running. In general, all that needs to be done is pass a
module object to the imp.reload() function (or just reload() in Python
2.x), and the module will be reloaded from its source file.

There are a few potential complications, however.

If any other code references symbols exported by the reloaded module, they maystill be bound to t

posted by Jon Parise on October, 27

Reloading Python Modules

Thu, 26 Nov 2009 18:52:17 -0800

There are a few potential complications, however.

If any other code references symbols exported by the reloaded module, they maystill be bound to t

posted by Jon Parise on November, 26

Twisted Python and Bonjour

Sun, 15 Nov 2009 18:12:10 -0800

Bonjour (formerly Rendezvous) is Apple’s service discovery protocol. It
operates over local networks via multicast DNS. Server processes announce
their availability by broadcasting service records and their associated ports.
Clients browse the network in search of specific service types, potentially
connecting to the service on the advertised port using the appropriate network
protocol for that service.

A common example of Bonjour in action is iTunes’ music library sharingfeature. iTunes shari

posted by Jon Parise on November, 15

Classless in-addr.arpa. Delegation

Sun, 15 Nov 2009 18:15:49 -0800

Classless in-addr.arpa. delegation allows network administrators to provide
authoritative reverse DNS on subnets that don’t fall on octet boundaries.
This is especially useful for subnets comprised of less than eight bits in the
host portion of the address (i.e. smaller than a class C).

There are two important things to remember: first, we’re dealing withclassless subnets, meaning they don’t align themselves neatly with IPv4’soctet boundaries (like a class A, B, C, D, or E network); and second, o

posted by Jon Parise on November, 15

Virtual Ethernet Tunneling

Sun, 15 Nov 2009 17:56:34 -0800

Overview

posted by Jon Parise on November, 15