The different between an SMTP proxy and a SMTP relay

This is one of those distinctions that is both obvious and obscure.

SMTP proxies and SMTP relays both sit between two machines; call themthe outside client and the inside mail server, as in the case of ourexternal mail gateway .

A SMTP proxy is synchronous . When it gets a SMTP connection from theoutside client, it establishes an SMTP conversation with the inside mailserver. When it receives a SMTP command from the outside client, itapplies its own processing (if any), sends the command on to the


My impressions of Google Chrome so far

My first impression of Chrome is that it's fast. My torture test isFlickr's new interface, which has some JavaScript that manages to bogdown my machines with every version of (Linux) Firefox that I've tried,including the 4.0 beta builds (which theoretically have significantlyfaster JavaScript). On Chrome it flies, to the point where it feelsfaster with JavaScript on than Firefox does with the JavaScript turnedoff in NoScript.

(This is in fact what motivated me to try Chrome


A Windows moment on my laptop

I had a Windows moment with my laptop today. I normally leave itsuspended instead of powered off, and when I unsuspended it I discoveredthat its networking had stopped working. The network-controlling widgetin my taskbar just said 'Networking unavailable', and the various systemmanagement interfaces were opaque about what might be wrong and why; thenetwork devices were there, they weren't reporting any obvious problems,and so on. The system just wasn't having anything to do with networking,whether wired or


The limitation of templates for web design changes

Given that DWiki is template-based, in theory I could fix my commentform design mistake from yesterday. All I would haveto do is revise the 'write a comment' template that's used here so thatit included the entry and the existing comment, as well as a preview ofyour new comment and the comment entry form itself.

Except not so fast, because this revised version would be a usabilitydisaster as I've described it. The problem is that all of the links tothe '


A design mistake in my comments form

It's slowly become obvious to me that one of the mistakes with the'add a comment' form here on WanderingThoughts is that it doesn'tshow you the entry and existing comments. I know, a while back I thought that this was a good idea, but I'vechanged my mind since then; it's a design mistake.

Why I know this is pretty simple; I base it on personal experience.Whenever I write a comment myself, I invariably wind up with two windowsopen


My (probably wrong) assumption about Flash on Fedora

In hindsight, it is somewhat peculiar that I spent a considerable timeusing Fedora 11 with a broken Flash setup instead of seriously lookinginto the situation. What happened is that I made a simple assumption: Iassumed that Flash and the associated infrastructure needed to run it ona 64-bit machine were second class citizens, looked down on and basicallyunsupported.

If I'd assumed that Fedora wouldn't leave Flash broken on 64-bitmachines, then it being broken on my machine was clearly


Why I hate the Solaris 10 version of /bin/sh

Every so often I discover some exceptional piece of braindamage inSolaris. Here is one of them, presented in handy illustrated form:

$ cat cdtest#!/bin/shcd /not/there || echo failedecho got here$ sh cdtest./cdtest: /not/there: does not exist

(No other output is produced.)

Oh yes, Solaris. Killing my script when a cd fails is just whatI want you to do, especially when this behavior is undocumented andcannot be turned


Another reason to hate $LANG and locales on Unix

Sometimes I'm slow; only recently did it occur to me how the $LANG sort misfeature and GNU comm's misfeature combine in an orgy of annoyance in a heterogenousenvironment.

Suppose that you have systems that changed their default localebetween operating system versions. As part of routine processing , you use comm to get the difference betweensomething on the local system and a global list. Well, oops. Even if youcarefully use sort on both versions, you are going to have problems.

As we saw earlier


A sudden realization about Unix access time updates and disk mirrors

I have a small confession: we have only recently turned off file accesstime updates on our fileservers . Whileturning off atime is one of the most common pieces of advicefor how to speed up overall filesystem performance (see here for oneexplanation why), we haven't felt that our filesystems were particularlyslow and sysadmins famously have a lot of inertia.

(What spurred me into action was being exposed to a bunch of stuff onZFS performance tuning, which caused me to start thinking again aboutsome long-


A clever blog anti-usability trick

Here is something that I have run into more than once. Through one of myvarious sources of links, I'll wind up somewhere reading an entry thatis called ', part 1'. At the end of the entry, I'lldecide that indeed, it was interesting, and I would like to see ifany part 2 has been written yet. So I try to look around.

The best answer would be a 'next part' or'related entries' link that