When iptables SNAT and routing happens, and how this is annoying
Per this famous iptables tutorial ( via ), andalso this more recent documentation ,locally generated IP packets go through multiple processing steps,both in iptables and in other things the kernel does:
- packets are given an initial routing, which assigns the source IPamong other effects
- iptables OUTPUT chain for the raw, mangle and then nat tables
- packets are re-routed in case iptables changed something here,although I believe their source IP will never be changed
- iptables OUTPUT chain for the (default) filter table
- iptables POSTROUTING chain for
I don't understand Linux iptables NAT as well as I should
I'm currently having a problem with my DSL link where aftera restart of the link (such as a power outage), I now can't reachany number of networks over it; unfortunately, quite a lot of thesenetworks are major hosting providers like AWS, Cloudflare, OVH,Google, and so on. Fortunately I can reach the other side of myIPSec tunnel and the other side of my IPSectunnel can reach all of these networks. For the most part all Iwant to do that
A bunch of my sysadmin work seems to be like gardening
Especially, it seems like weeding, or at least how I've read weedingdescribed (I'm not a gardener myself so I have limited experiencehere). By that I mean that it's plodding and often boring, andinvolves going through our systems to trim back or pull out entirelyvarious things that were once necessary (well, probably) but thathave been neglected and are now at least overgrown and perhapsoutright bad. It's painstaking work because I have to make surethat what I
We're probably going to see a major Certificate Authority de-trusted
I mentioned WoSign the other day .To be blunt, at least from my perspective things do not look forWoSign . Unlike some CAsthey do not seem to have been compromised or acting with actualmalice; however, they are behaving extremely sloppily, do not seemto care much about security, and certainly appear to be lying aboutmultiple issues. At this point it seems less like a question of ifthey should be de-trusted by browsers and more a question of when.
Under normal circumstances, this might be
Link: Actually using ed
Tom Ryder's Actually using ed ( via@davecheney )is a nice little walk-through of using the Unix ed editor to,well, edit some text. I've used ed a long time ago, and thisinspired me to fire it up again to follow along and play around abit; it was surprising how much I remembered. It was also nicereading about some advanced ed features that I either didn't knowabout or never used enough to remember.
(As always, I find
Some notes on curating the set of CAs that Firefox trusts
In light of recent events involving WoSign ( and there's more ), I decided to distrusttheir CA certificates in my Firefox setup. This turned out to bemuch more involved than I expected, but also much more educational.
This is not the first time I've done this sort of thing, or moreexactly this is not the first time I've tried to. And in that littleremark is a tale. When I've done this in the past, the CAs that Itold Firefox
Someone's exploiting Google's account recovery system to send spam
I've written before that spammers willeventually exploit any way of sending some user-supplied textto arbitrary email addresses. Today I got a beautiful exampleof this, where someone appears to be exploiting Google's processof managing account recovery options to send spam. Yes, really.
(I can't be entirely sure of what's going on because the entiremessage is in Chinese and I'm feeding it through Google Translatein order to understand it.)
The email was send to a pseudo
Why my smartphone is going to be an iPhone
I'm going to get a smartphone soon, not just for backup Internet but for other reasons too (and honestly,it's about time). When I do this, I will be getting an iPhone. Thismay surprise some people, but it isn't a recent decision; I decidedseveral years ago that my eventual smartphone would almost certainlybe an iPhone, and nothing I've seen since then has changed my mind.
(If anything, the more I've learned the more I
Modules should never raise core Python exceptions
Today I discovered that the zipfile module raises RuntimeError if you ask it to read a file from an encrypted ZIP archive and donot give it the right password (or don't give it a password at all). I wasn't happy .Apparently it isn't obvious to the people who maintain Python'sstandard library (and who updated it for Python 3) why this is aterrible idea ( not that I'm surprised about that ).
Here is a simple rule for module writers:
Using Magit to selectively discard changes in your git working tree
Suppose, not entirely hypothetically, that you have been hackingaround with something that uses git and you've wound up with somecode changes in your working tree that have definitely turned outto not be what you want. If these changes are the only changesyou've made to a particular file, you can restore the file with' git checkout '. If all of the other changes to the file are onesthat are ready to commit, you can use Magit to selectively stagethem , commit what you'