When it started out, the Spamhaus CSS was primarily there to list IP addresses and address ranges usedfor snowshoe spamming (this wasexplicitly covered in the announcement of the Spamhaus CSS , and even helped givethe CSS its name). However, things have changed somewhat since 2009,both with Spamhaus and perhaps with snowshoe spammers themselves.Specifically, the CSS is now described as:

The Spamhaus CSS list is an automatically produced dataset of IPaddresses that are involved in sending low-reputation email. CSSmostly

Up until very recently , I wouldhave confidently told you that a Linux process's 'virtual size' was always at least as large as its residentset size . After all, how could it beotherwise? Your 'virtual size' was the total amount of mapped addressspace you had, the resident set size was how many pages you had inmemory, and you could hardly have pages in memory without havingthem as part of your mapped address space. As Julia Evans hasdiscovered ,this is apparently not

Some time ago I wrote up some notes on OpenSSH's optional hostnamecanonicalization . At the time I had justcautiously switched over to having my OpenSSH setup on my workstationcanonicalize my hostnames, and I half expected it to go wrongsomehow. It's been just over a year since then and not only hasnothing blown up, I now actively prefer having OpenSSH canonicalizethe hostnames that I use and I've just today switched my OpenSSHsetup on our login servers over to do this and cleared out my ~

A number of years ago I wrote an entry on what you can find outabout the memory usage of your Linux programs ,and in it I cast cold water on what top reports as SHR on thegrounds that it was only vaguely documented. There are two piecesof good news. The first is that I can now tell you what the fieldmeans and where it comes from, and the second is that it is actuallyquite well documented in the latest top manpage . That top manpageis well worth your attention,

My department has now been running our Unix computing environmentfor a very long time (which has some interesting consequences ). When you run a Unix environment over thelong term, old historical practices slowly build up and get carriedforward from generation to generation of the overall system, becauseyou've probably never restarted everything from complete scratch.All of this is an elaborate route to say that as part of our localpassword propagation infrastructure , wehave a program that checks /etc/passwd and /etc/group to

I have griped before ( and recently ) about howmuch of a pain it is to try to keep the number of kernels thatUbuntu installs on your machines under control. Writing your ownscript to remove obsolete kernels is fraught with challenges, butas it turns out I think we can do what we want with ' apt-getautoremove ' and some extra work.

First, as Ewen McNeill saidin a comment here back in 2015, it's thecase that ' apt-get autoremove '

Today in an email message with the subject of [TUHS] Releaseof 8th, 9th and 10th Editions Unix ,Warren Toomey announced that the Unix Heritage Society has now gained permission to make the sourcecode of Research Unix's 8th, 9th, and 10th editions available forthe usual non-commercial purposes. This apparently is the resultof a significant lobbying campaign from a variety of Unix luminaries .The actual source trees can be found in TUHS' archive area forResearch distributions

We're currently running OmniOS r151014 on our fileservers , which is the current long term supportrelease (although we're behind on updates, because we avoid themfor stability reasons). However, per the OmniOS release cycle , there's a newLTS release coming this summer and about six to nine months later,our current r151014 version will stop being supported at all.Despite what I wrote not quite a year ago about how we might not

In a comment on my entry on how I think you have lots of Let'sEncrypt accounts , Aristotle Pagaltzis asked a good question:

Taking this logic to its logical conclusion: as long as you canarrange to prove your control of a domain under some ACME challenge atany time, should you not immediately delete an account after obtaininga certificate through it?

(Granted – in practice, there is the small matter that deletingaccounts appears unimplemented, as per your other entry…)

Let's take the last