Posted by mark.
Results > Posts Filed Under > Linux
Oct
29
Posted by mark.
I’m going to use the term “Cloud” in this post which I despise for it’s nebulosity. The press has bandied the term around so much that it means everything from the Net as a whole to Google Apps to virtualization. My “cloud” means a cluster of virtual machines.
I’ve been a huge fan of Mark Shuttleworth for a long time. Besides the fact that his parents have great taste in first names, he’s taken his success with Thawte and ploughed it …
Oct
20
Posted by mark.
Well the title says it all. Internet routers live at Layer 3 [the Network Layer] of the OSI model which I’ve included to the left. HTTP and HTTPS live at Layer 7 (Application layer) of the OSI model, although some may argue HTTPS lives at Layer 6.
So how is it that Layer 3 devices like routers treat HTTPS traffic differently?
Because HTTPS servers set the DF or Do Not Fragment IP flag on packets and regular HTTP servers do not.
This matters …
Oct
17
Posted by mark.
I’ve spent the last 5 days agonizing over a very hard problem on my network. Using curl, LWP::UserAgent, openssl, wget or any other SSL client, I’d see connections either timeout or hang halfway through the transfer. Everything else works fine including secure protocols like SSH and TLS. In fact inbound SSL connections work great too. It’s just when I connect to an external SSL host that it hiccups.
If you remember your OSI model, SSL is well above layer 3 (IP …
Oct
16
Posted by mark.
It took me a while to find this – I needed it for testing purposes, nothing malicious. If you’d like your web server somewhere on the web to pretend to be any other web server, even a secure one, you can do the following. x.x.x.x is your own server and y.y.y.y is the ip of the server you’re trying to mirror. I’m also assuming you only have one network card in the machine and it’s called eth0. The following will …
Oct
15
Posted by mark.
While I upgrade to Karmic, here’s a quick setup to get a virtual ubuntu server running on a real ubuntu server:
As root:
ubuntu-vm-builder kvm jaunty –hostname dev2 –addpkg openssh-server vim -d /usr/local/vms/dev2 –mem 256 –libvirt qemu:///system
This will create a jaunty jackalope ubuntu virtual server using the KVM hypervisor. The hostname will be dev2. It will add the openssh-server package as well as vim. It will put it in the /usr/local/vms/dev2 directory. It’ll allocate 256 Megs of memory for the machine. The …