Following up the previous case , here's something weran into recently.

Imagine that you want to pull lines out of /etc/shadow for specificlogin names; you'd use, for example, ' grep "^${UNAME}:" /etc/shadow '.Now imagine that some of your login names include '$', so you want togenerate a version of $UNAME with the '$' quoted.

So what do you have to write? It turns out that you

Here's something I would like to grind into various people programmingcallback email address verification:

Don't do callback email address verification with a MAIL FROM of <>unless the address has actually sent you email .

Why? Because if an address never sends any email to start with, it maynot be willing to receive bounces (the major source of email from <>).Blocking null MAIL FROMs from sending email to such addresses is acompletely rational way to block bad bounces from forged spam runs.

The

After yesterday , I decided to spend some timeworking out how many of the root DNS servers are reachable overour Internet II link. The answer surprised me: 9 out of the 13root nameservers are reachable over Internet II .

(The necessary disclaimer: your view of what is reachable over InternetII may well vary from ours due to routing and local policy issues.)

We prefer to send packets over our Internet II link, so working out thisnumber was relatively simple. I got a list of the IP