Encountered paperwork: "Using scanners and OCR to grep paper documents the easy way" from an LWN Article.
Sunday, November 13. 2016
Semi-automatic document scanning with Paperwork
Off-Line IMAP (referenced from NotMuch)
Microsoft Outlook will typically replicate the contents of an IMAP mailbox locally to facilitate off-line access to email. I have been looking for a similar function for opensource based packages. I found it.
OfflineIMAP is a GPLv2 software to dispose your mailbox(es) as a local Maildir(s).
For example, this allows reading the mails while offline without the need for your mail reader (MUA) to support disconnected operations.
OfflineIMAP will synchronize both sides via IMAP.
Code is maintained at github.
I found this when seeing Notmuch -- Just an email system at LWN: A year with Notmuch mail.
2018/02/12 - astroid - a lightweight and fast Mail User Agent that provides a graphical interface to searching, displaying and composing email, organized in threads and tags. Astroid uses the notmuch backend for blazingly fast searches through tons of email. Astroid searches, displays and composes emails - and rely on other programs for fetching, syncing and sending email.
OpenFlow Thinkings
t has taken a while, but I think I understand how some flavours of SDN work.
In CiscoLand, at the hardware level, CEF is a flow based forwarding mechanism. All the higher layer routing protocols like bgp, ospf, rip, etc, are used to build that flow table. I think Cisco's ACI is designed to manipulate those flow tables directly through some set of off-box oob controllers. These flows are monitored through Netflow, sFlow, OpenFlow telemetry commands, and the like. So flows are integral to how networks work. How they are controlled is the question.
I used to be of the mentality that this central control created points of failure in the network. But if boxes can maintain state during a controller failure or outage, then it isn't so bad. In addition, many initial talking points mention that flow tables needed to be dynamically populated, which requires punting packets to the controller, which really slows things down.
But many networks have a reasonably static topology. This enables flow bundles to be pre-populated and thus hardware forwarding can be used for the majority of the traffic, if the flow rules are general enough. From a high level perspective, then the issues arise when network failures occur. How does the network heal itself around those failures points? Some answers I am still looking into.
In the open source world, Linux, in the kernel forwarding plane, also maintains a flow table. sFlow can be used to monitor flows. There are netflow add-ons to monitor those flows. Static routes and things like Quagga are used to define the rules for how flows are setup.
So, enters the concept of OpenFlow, which is a set of rules used to manage those flow tables directly. Either locally, or through some off-box controller. (I have been looking into Ryu at the moment).
When using layer 3 network protocols like bgp, et.al., the flow rules are typically defined based upon destination ip address.
With OpenFlow, flows can be specified on a number of different combinations of addresses, ports, mac addresses, encapsulations, ...
Now take that concept, and make the realization that you can create a distributed firewall, because the network itself can provide firewall and associated security features. Rather than creating flow rules based upon destination address, ... with the added granularity, flow rules can be specified that only specific types of traffic (eg port 80, or esp, or ...) go through various parts of the network, and traffic not matching those flow rules go somewhere else, say like a honey-pot or something.
And with various forms of encapsulation from edge to edge, various forms of vrf/vpn/segmentation are inherently supplied.
So, it is conceivable that the central points of congestion like big central firewalls can be eliminated, and the security and privacy can be distributed throughout the network. Kind of like MPLS/VPLS on steroids.
From the open source perspective, I have just started going through the examples for OpenVSwitch (OVS) and its companion product Open Virtual Networking OVN at Spinhirne's Blog . The examples show some single points of failures, but I think I know how to make those better. It is looking promising based upon what I've seen so far, but have more under-the-hood looking to do.
Auto-Starting ssh-agent in KDE
Sometime back, the maintainer of kde-agent removed the package. As a work around for providing a solution to ssh-agent for all session terminals, I lift the following solution from ArchLinux: ssh-agent support removed from kde-agent and ArchLinux: ssh keys:
In ~/.config/systemd/user/ssh-agent.service, put the following code:
[Unit] Description=SSH key agent [Service] Type=forking Environment=SSH_AUTH_SOCK=%t/ssh-agent.socket ExecStart=/usr/bin/ssh-agent -a $SSH_AUTH_SOCK [Install] WantedBy=default.target
Append to ~/.bashrc:
export SSH_AUTH_SOCK="$XDG_RUNTIME_DIR/ssh-agent.socket"
Enable the service with:
systemctl --user enable ssh-agent
And start with:
systemctl --user start ssh-agent
Disable Windows 10 Login Background
- Run regedit.
- In Registry Editor, go to following key: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System
- In right-side pane, create new DWORD DisableLogonBackgroundImage and set its value to 1.
- Restart your computer and it'll remove the background image from login screen.
If you want to restore Login Screen background image in future, delete the DWORD DisableLogonBackgroundImage.
From How To Change Sign-in/Login Screen Background Picture In Windows 10
Pictures are located in C:\Windows\Web\Screen
One other setting: Settings -> Ease of Access -> Other Options -> Show Windows Background -> Off