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SSH tunnelling
by Mark Rogers 28 Mar '17

28 Mar '17

I need to access the web server on a VM in my office, from my laptop. I have SSH access to an intermediate PC and from there to the VM. Ie: Laptop -> PC -> VM How do I set up a tunnel from laptop through PC to VM to give me access to port 80 on the VM? If relevant: Each of the two SSh connections will require (different) user/password. Mark -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) 21 Drakes Mews, Milton Keynes, MK8 0ER

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Re: [ALUG] Machine slows down
by Christopher Dawkins 23 Mar '17

23 Mar '17

> Several times over the past few weeks I've had my PC (Ubuntu 16.10*) > apparently lock up: desktop stops changing (clock stops updating) but > the mouse (usually) continues to move. Sometimes I can SSH in, > although more often I can get as far as entering username/password but > never reach a terminal prompt. Run 'top' in a console window on the screen beforehand. I find Firefox can do this with some web sites that are too javascript-heavy, load averages up to 50 or more. -- Christopher Dawkins Archivist, Felsted School http://archives.felsted.org Garnetts Corner, Jollyboys Lane North, Felsted, Dunmow, Essex CM6 3DU cchd(a)pjcd.org 07816 821659 01371 821076

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Digital East Anglia meetup
by Ewan Slater 23 Mar '17

23 Mar '17

If anyone's interested: https://www.meetup.com/digital-east/events/238348094/?a=socialmedia

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Delay in sending mail
by Jenny Hopkins 22 Mar '17

22 Mar '17

Hello, Can anyone suggest why sending IMAP mail from either icedove, thunderbird, claws on a client is taking about a minute (about ten seconds "connecting to server" then over 30 seconds with "delivering mail"), whereas using mutt it goes in an instant? I must have something misconfigured somewhere, but don't know where to start looking - exim4 and dovecot logs on the server aren't showing anything up of interest. Thanks for any suggestions, Jenny

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[ALUG Announce] ALUG Norwich Pub Meet Thursday 9th March
by Viperfang 06 Mar '17

06 Mar '17

ALUG Announce Please send announcements to Announce(a)lists.alug.org.uk Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce ----- Hello Norwich Aluggers, Our monthly ALUG Norwich social meeting will be held this Thursday, 9th March at The Coach and Horses (82 Thorpe Road, Norwich, NR1 1BA). The meeting officially starts at 8pm, although some people may arrive earlier. More information on those people can be found on the list and the IRC channel. If you are unsure if you will recognise us then make yourself and your intent to attend known by either posting on list or visiting us on IRC so we can look out for you rather than hiding in the corner. Optionally you could ask at the bar if they know where the geeky computer weirdos are and they'll point you in the right direction (seriously!). Another possibility is look for heaps of electronics on a table that may possibly look like movie props that would used for detonating explosives. Feel free to bring electronics/laptops/gadgets to the meet, you will by no means be alone. Ben Bewick aka Viperfang NB: This mail is automated, please refer to the usual sources for more information. ALUG Contact Details: Website : http://www.alug.org.uk/ IRC : #alug on irc.alug.org.uk List : http://lists.alug.org.uk/mailman/listinfo Twitter : http://twitter.com/anglianlug Identica: TBA Facebook: http://www.facebook.com/group.php?gid=2381613902 ----- Send discussion replies to main(a)lists.alug.org.uk (Reply-To set) Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce

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2600 meeting at 18:00 on Friday the 3rd March.
by Viperfang 28 Feb '17

28 Feb '17

Quick heads up about this months Norwich 2600 meeting, more info at http://www.norwich2600.co.uk

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Re: [ALUG] Automated IMAP client
by Christopher Dawkins 27 Feb '17

27 Feb '17

> I'm thinking a simple ticketing system would be good, although I've > not yet found a "simple" ticketing system that doesn't try to do so > much as to be too big a job to implement it in the first place. Nothing is simple, except for gurus, but try (Request Tracker). -- Christopher Dawkins Archivist, Felsted School http://archives.felsted.org Garnetts Corner, Jollyboys Lane North, Felsted, Dunmow, Essex CM6 3DU cchd(a)pjcd.org 07816 821659 01371 821076

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Automated IMAP client
by Mark Rogers 27 Feb '17

27 Feb '17

Are there any tools to set up an automated IMAP client? By which I mean I want to set up some software on a headless Linux box which connects to an account on an IMAP server elsewhere. It could then be configured to perform actions on received email, such as filter it, move it to folders, forward it to people based on various criteria, etc. It seems like the sort of thing that must exist but I'm clearly picking the wrong things to Google for... Mark -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) 21 Drakes Mews, Milton Keynes, MK8 0ER

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What's a fast way to check for something on LAN?
by Chris Green 22 Feb '17

22 Feb '17

I want a fast (as in less than a second, not 'computer fast') way of checking if a particular private IP is present on the LAN. I need this for use in a match construct in an SSH config file, e.g.:- # # # odin may be remote or local from t430 # Match host odin exec "sh -c 'hostNotLocal 192.168.0.104'" ProxyCommand ssh cheddar nc -q0 localhost 51234 Currently 'hostNotLocal' is:- #!/bin/bash # # # Test if specified host is ping'able # ! ping -c 1 $1 >>/dev/null 2>&1 The problem with this is that on any LAN except one using 192.168.0.xxx it takes several seconds to decide that 192.168.0.104 isn't there. For any nit-pickers, yes I know if I just happen to be connected to a LAN which isn't where 'my' 192.168.0.104 is I'll get a false positive but I can live with that. I just want a fast way of knowing that 192.168.0.104 *isn't* there. -- Chris Green

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Correct MX record configuration
by Chris Green 20 Feb '17

20 Feb '17

This may relate to my recent long question about loss of E-Mail. Can anyone tell me *exactly* how an MX record for my home server zbmc.eu should be confiugured? Currently it's configured to point to the 'root' A record for zbmc.eu, so the MX record is for zbmc.eu also:- chris@cheddar$ host zbmc.eu zbmc.eu has address 84.92.49.234 zbmc.eu mail is handled by 10 zbmc.eu. chris@cheddar$ However I *think* this may be wrong and I should create a second A record for the same IP address and point the MX record to that instead. I don't really understand why this should make any diffrerence though. Any experts (or at least people who know more than me) here? -- Chris Green

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Re: [ALUG] I need an E-Mail expert to help me solve this
by Phil Ashby 19 Feb '17

19 Feb '17

On 19/02/17 12:00, Chris Green <cl(a)isbd.net> wrote: > > I have an E-Mail requirement/problem that I've wasted several hours on over the past few days to > little effect. Maybe someone here can help. > > My home (linux) machine runs all the time and hosts the domain zbmc.eu which is registered at > gandi.net. The zone file there is configured to point at my home machine and the MX record is > set up too:- > chris@cheddar$ host zbmc.eu > zbmc.eu has address 84.92.49.234 > zbmc.eu mail is handled by 10 zbmc.eu. > chris@cheddar$ 84.92.49.234 is my PlusNet ADSL connection. > > ..[lots of testing that indicates 'something' is blocking SMTP on some routes, but not all...] Hi Chris, I have almost the same setup as you, an external/public server (mail.ashbysoft.com) that forwards mail to an internal/private server at home (phil.ashbysoft.com, on PlusNet), my external server is in a co-lo facility and managed by me, rather than a 3rd part but hey, it's still working so it doesn't look like PlusNet per se.. I tried a few tests for your host: - from my home network (via NAT, PlusNet): phlash@zaphod:~$ host zbmc.eu zbmc.eu has address 84.92.49.234 zbmc.eu mail is handled by 10 zbmc.eu. phlash@zaphod:~$ telnet zbmc.eu 25 # not looking good for inbound connectivity on 25 Trying 84.92.49.234... ^C phlash@zaphod:~$ telnet zbmc.eu 587 # nor the alternative SMTP submission port 587 Trying 84.92.49.234... ^C - from my external server (via NAT, Virgin Media): phil:~$ telnet zbmc.eu 25 # still no joy Trying 84.92.49.234... ^C phil:~$ telnet zbmc.eu 587 # kind of expected by now :/ Trying 84.92.49.234... ^C phil:~$ ping zbmc.eu # just checking the endpoint is up :) PING zbmc.eu (84.92.49.234) 56(84) bytes of data. 64 bytes from chrisisbd01.plus.com (84.92.49.234): icmp_seq=1 ttl=243 time=25.2 ms 64 bytes from chrisisbd01.plus.com (84.92.49.234): icmp_seq=2 ttl=243 time=25.5 ms 64 bytes from chrisisbd01.plus.com (84.92.49.234): icmp_seq=3 ttl=243 time=21.6 ms ^C - last check for my own connectivity, to prove it's not local to me: phil:~$ telnet phil.ashbysoft.com 25 # looks OK Trying 84.92.108.193... Connected to phil.ashbysoft.com. Escape character is '^]'. 220 phil.ashbysoft.com ESMTP Exim 4.88 Sun, 19 Feb 2017 15:05:43 +0000 quit My conclusion so far would be that you have local firewalling / filtering issues that are permitting traffic from the TsoHost servers but nowhere else? Are you running fail2ban and it has been a bit enthusiastic (this has got me in the past, blocking the kids mobiles when they bork their password a couple of times)? What about port forwarding arrangements, just for specified external IPs? NB: I have switched to port 587 for all my immediate users (family & friends, you know the score!) to submit mail from their clients through my relay service, as they were finding that port 25 was blocked outbound by whatever ISP they were using at the time (typically mobile / public services like The Cloud). Hope this helps, Phil.

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Managing cron and similar E-Mails from headless systems
by Chris Green 19 Feb '17

19 Feb '17

I have several headless systems doing useful work around the place:- A Raspberry Pi providing local DNS and DHCP A Beaglebone Black on our boat monitoring temperatures and batteries An old desktop doing backups in the garage etc. Most of these have one or more cron jobs running periodic rsync backups, copying data, etc. If the cron job has an error then it sends E-Mail to the owner of the job ('chris' in most cases, might be root in a couple). It's (moderately) easy to set up an MTA and /etc/aliases so that the messages are sent to my normal E-Mail. However I can't come up with a straightforward way of indicating where the messsage is *from*. You can't just invent a domain name for the headless system because that gets the E-Mail rejected by intermediate systems that try and look up the sender host name. Cron doesn't seem to have any mechanism for setting the sender's name, cron errors just come from 'root@'. Can anyone suggest a neat way of handling this so that I know where the errors are coming from? -- Chris Green

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I need an E-Mail expert to help me solve this
by Chris Green 19 Feb '17

19 Feb '17

I have an E-Mail requirement/problem that I've wasted several hours on over the past few days to little effect. Maybe someone here can help. My home (linux) machine runs all the time and hosts the domain zbmc.eu which is registered at gandi.net. The zone file there is configured to point at my home machine and the MX record is set up too:- chris@cheddar$ host zbmc.eu zbmc.eu has address 84.92.49.234 zbmc.eu mail is handled by 10 zbmc.eu. chris@cheddar$ 84.92.49.234 is my PlusNet ADSL connection. I have several domains hosted at TsoHost with associated E-Mail addresses (e.g. chris(a)isbd.co.uk, chris(a)isbd.net, cl(a)isbd.net) These all eventually forward their E-Mail from the TsoHost servers to chris(a)zbmc.eu. I run a postfix server on my home machine which receives these E-Mails and puts them in my mail spool. This has been working fine for several years. However I now want to send E-Mail from the 'outside world' to chris(a)zbmc.eu. The specific requirement is to send errors from cron on various SBCs to me and I originally thought it was a misconfiguration at the sending end was the problem but it's more general. No mail sent from outside to chris(a)zbmc.eu arrives on my home machine, it just disappears, no errors, no bounces, nothing. Bit it works from the TsoHost cloud servers, why can they send E-Mail successfully to chris(a)zbmc.eu whereas no one else can? I have done lots of tests and experiments so far:- I've tried sending from three different sites (PlusNet, Gandi and a Linux box) to chris(a)zbmc.eu, mail just disappears. Identical E-Mail sent to chris(a)isbd.net arrives OK. I have a postfix server set up on my Beaglebone black in France (to send the cron messages). If I monitor the mail.log file when connecting to the SMTP server at TsoHost (mail3.gridhost.co.uk) the logging is exactly the same for mails sent to chris(a)zbmc.eu as for mails sent to chris(a)isbd.net. Wierdly (and this is what confused me somewhat at the start) I have an identical postfix setup on a Raspberry Pi on my home LAN, also for sending cron errors. It connects directly to the same SMTP server at TsoHost as the Beaglebone does. However E-Mail to chris(a)zbmc.eu from the Pi works! So it would seem that there's something 'out there' that's routing mail for zbmc.eu to the wrong place (or nowhere), but it doesn't get at the mail sent from within TsoHost for some reason. I.e. TsoHost seems to do what I hoped/expected with E-Mail for chris(a)zbmc.eu but no one else does. Help! :-) -- Chris Green

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Re: [ALUG] Managing cron and similar E-Mails from headless systems
by mark fernandes 17 Feb '17

17 Feb '17

Looks live reverse alias are what you need... https://linux.die.net/man/8/ssmtp

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[ALUG Announce] ALUG Norwich Pub Meet Thursday 9th February
by Viperfang 06 Feb '17

06 Feb '17

ALUG Announce Please send announcements to Announce(a)lists.alug.org.uk Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce ----- Hello Norwich Aluggers, Our monthly ALUG Norwich social meeting will be held this Thursday, 9th February at The Coach and Horses (82 Thorpe Road, Norwich, NR1 1BA). The meeting officially starts at 8pm, although some people may arrive earlier. More information on those people can be found on the list and the IRC channel. If you are unsure if you will recognise us then make yourself and your intent to attend known by either posting on list or visiting us on IRC so we can look out for you rather than hiding in the corner. Optionally you could ask at the bar if they know where the geeky computer weirdos are and they'll point you in the right direction (seriously!). Another possibility is look for heaps of electronics on a table that may possibly look like movie props that would used for detonating explosives. Feel free to bring electronics/laptops/gadgets to the meet, you will by no means be alone. Ben Bewick aka Viperfang NB: This mail is automated, please refer to the usual sources for more information. ALUG Contact Details: Website : http://www.alug.org.uk/ IRC : #alug on irc.alug.org.uk List : http://lists.alug.org.uk/mailman/listinfo Twitter : http://twitter.com/anglianlug Identica: TBA Facebook: http://www.facebook.com/group.php?gid=2381613902 ----- Send discussion replies to main(a)lists.alug.org.uk (Reply-To set) Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce

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2600 meeting at 18:00 on Friday the 3rd February.
by Viperfang 31 Jan '17

31 Jan '17

Quick heads up about this months Norwich 2600 meeting, more info at http://www.norwich2600.co.uk

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How to get rid of these corrupted files?
by Chris Green 28 Jan '17

28 Jan '17

I have some files/directories which have obviously become corrupted. The disk checks out OK with fsck though and I don't want to reformat it. One of the directories in question is as follows:- total 40 d-wxr-S-wT 2 3775186858 3662599049 4096 Sep 11 1991 18039.dat ---xr-srwT 30 3023870906 1270584165 45056 Mar 1 1938 18591.dat -r-x-wxr-T 30 2743781339 1057221377 28672 Jun 6 1929 18684.dat Even as root I can't seem to do anything with this, both rm and chmod fail with 'permission denied'. So, how do I do anything with these? -- Chris Green

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Wanted - plain, simple, GUI address book
by Chris Green 28 Jan '17

28 Jan '17

I use mutt for E-Mail but I'm looking for a GUI address book because my address book requirements extend well beyond (but include) E-Mail addresses for mutt. I have been using the Contacts app in Owncloud with pycardsyncer keeping a local address list in sync with the Owncloud Contacts for mutt to use. However I'd like to make things simpler and better, the existing set-up has some disadvantages (for me) :- The Owncloud Contacts app is not very good, in particular you can't sort by Last Name which really bugs me. I'd really prefer to keep addresses wholly locally rather than on the cloud (even though it's my own cloud). Apart from anything else I'm quite often not able to access the internet and I still want my addresses and to be able to update them. The pycardsyncer (plus pc_query) application is 'deprecated', it's being superseded by vcardsyncer and some other bits and pieces. They're not in the Ubuntu repositories though and I prefer not to go 'ex repository'. The current set up is a fairly complicated way to fulfil a simple requirement. So I'm after a nice, simple, GUI address book program for my Linux desktop and laptop. I'm happy to use a mail program whose address book is easily accessible without navigating past the mail bit (e.g. like Thunderbird, but Thunderbird is overkill). I either want a mutt accessibility option or for the data to be kept in something sensible like a sqlite database that I can quickly write a simple script for to feed mutt. It must support postal addresses, phone numbers, etc. and preferably have some notes/comments ability too. I'd prefer something in the Ubuntu repositories though something in Python that I can maintain myself is also OK. Any suggestions anyone? -- Chris Green

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How to unmount an ext4 file system, journalling makes it permanently busy
by Chris Green 13 Jan '17

13 Jan '17

Is there any way to unmount an ext4 filesystem without shutting down? I can do it easily by going to single-user mode or removing the filesystem from /etc/fstab and rebooting but both of these require the system to be shut down. However it seems to be impossible otherwise because the journalling process makes the filesystem busy. Is this right? -- Chris Green

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Re: [ALUG] How to get rid of these corrupted files?
by Srdjan Todorovic 11 Jan '17

11 Jan '17

On 11 Jan 2017 09:58, "Chris Green" <cl(a)isbd.net> wrote: On Tue, Jan 10, 2017 at 10:10:42AM +0000, Chris Green wrote: > > Otherwise, I'm out of ideas. > > > So am I, I'm copy all the files of the drive and I'm going to re-make > the file systems. > ... and now, 16 hours later I'm seeing some errors. I've run 'mkfs.ext4 -c -c /dev/sdb1 and on the *second* pass I'm seeing some errors. The first 0xAA pass got no errors but the pass that's running now, writing 0x55, is getting some errors. So, presumably, that's what the problem is. However it's strange that nothing else was showing any errors, SMART reported nothing at all and Did smart long test complete at all? Im under the impression it only works when disk is idle, so if you were fscking then it wouldnt have been idle. Thats certainly been my experience recently. Regards Srdj

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[ALUG Announce] ALUG Norwich Pub Meet Thursday 12th January
by Viperfang 09 Jan '17

09 Jan '17

ALUG Announce Please send announcements to Announce(a)lists.alug.org.uk Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce ----- Hello Norwich Aluggers, Our monthly ALUG Norwich social meeting will be held this Thursday, 12th January at The Coach and Horses (82 Thorpe Road, Norwich, NR1 1BA). The meeting officially starts at 8pm, although some people may arrive earlier. More information on those people can be found on the list and the IRC channel. If you are unsure if you will recognise us then make yourself and your intent to attend known by either posting on list or visiting us on IRC so we can look out for you rather than hiding in the corner. Optionally you could ask at the bar if they know where the geeky computer weirdos are and they'll point you in the right direction (seriously!). Another possibility is look for heaps of electronics on a table that may possibly look like movie props that would used for detonating explosives. Feel free to bring electronics/laptops/gadgets to the meet, you will by no means be alone. Ben Bewick aka Viperfang NB: This mail is automated, please refer to the usual sources for more information. ALUG Contact Details: Website : http://www.alug.org.uk/ IRC : #alug on irc.alug.org.uk List : http://lists.alug.org.uk/mailman/listinfo Twitter : http://twitter.com/anglianlug Identica: TBA Facebook: http://www.facebook.com/group.php?gid=2381613902 ----- Send discussion replies to main(a)lists.alug.org.uk (Reply-To set) Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce

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2600 meeting at 18:00 on Friday the 6th January.
by Viperfang 03 Jan '17

03 Jan '17

Quick heads up about this months Norwich 2600 meeting, more info at http://www.norwich2600.co.uk

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How to set system date/time automatically at power up, no CMOS clock
by Chris Green 15 Dec '16

15 Dec '16

I have a BeagleBone Black system which monitors things on a boat. When it powers up the time is basically random, there's no CMOS clock to give it a start. Thus I need a way to get it to about the right time and date for ntpd to take over and keep it correct. What's the normal way of doing this? It needs to be automatically run at startup. -- Chris Green

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Re: [ALUG] main Digest, Vol 138, Issue 3
by Christopher Dawkins 15 Dec '16

15 Dec '16

>> 1. Re: Building an (air gapped) offline Linux laptop as a >> newbie to Linux (mick) > What is your threat model? A question I wonder too, but welcome to the Unix world. If you have been previously on Windows I suppose you would be worried about security, but I'd suggest you stop worrying now. Unless you are in a public position and disliked by many, such as being Donald Trump, since almost any networked system can be breached by a skilled and determined opponent. If the threat to you is such that you need an airgapped machine then I wonder how you plan to protect the machine itself, as apart from some special products (iPhones?) it's usually possible to get inside a machine if you can get it to your laboratory bench. So the important questions are not software ones, they are: Do you live in a bunker or in a house? How many security men do you have guarding this bunker or house? How many steel or six-foot-concrete walls are there between you and the outside? If you have glass windows, is the glass toughened and more than several inches thick? Do you ever leave the house with the machine inside and not guarded by a small army? Would you ever carry the machine outside without a military guard? Do you search and scan all your visitors? Will your machine have internal explosives wired to all the case screws? If you don't apply the measures suggested by the questions above, the airgap could prove to be of no use, so much so that it's not worth bothering about. -- Christopher Dawkins Garnetts Corner, Jollyboys Lane North, Felsted, Dunmow, Essex CM6 3DU cchd(a)pjcd.org 07816 821659 01371 821076

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Building an (air gapped) offline Linux laptop as a newbie to Linux
by Ian Henderson 14 Dec '16

14 Dec '16

Hi, all, I am new to Linux. I'm porting over to Ubuntu 16.04 LTS with the Unity desktop from Windows 10. I want to keep things as simple (and hopefully therefore as reliable) as possible, for home/office critical use. I also want to stick to the main and universe repositories. Because prices were much lower for Linux-compatible laptops than with Win 10 installed, I can afford two. I plan to divide them into one for critical offline-only use, and the other for universal online use. I will air-gap the two. But it also means that I need to complete the final build of the offline air-gapped laptop ahead of porting data, after which it will not go online again (unless for a wipe and rebuild). For the offline-only laptop, I am looking at the following range of apps. Could I ask that you check my ideas, and offer suggestions and advice, please.:- 1) An office-like suite, for which I will be using LibreOffice, which is installed by default. 2) I need a whole-directory and free space overwriting utility, as well as the means to securely delete individual files. My understanding is that shred and wipe are available by default. I am looking at bleachbit for the whole-directory and free space wiping. But the software centre says "sudo" for this app: does that mean it has elevated privileges and is this a bad idea? 3) GtkHash for SHA256 etc. cryptographic hashes, primarily to verify backups. 4) Can anyone suggest an archiving utility which also verifies the files within the archive (I can then hash the archive file backup)? Archiving does not necessarily have to include compression. Are any installed by default? 5) GnuPG. I understand that this is installed by default? Am I correct that I can encrypt with password files if transferring on FAT32 USB or CD/DVD with this? Is it GUI? 6) CD/DVD burning, including both copying using a single optical drive, ordinary file burning and creating bootable CD/DVD from ISO images. I'm looking at Brasero for this. Can anyone suggest any other apps I should include ahead of locking off the build? I'm also assuming that the default 16.04 LTS supports formatting USB sticks to ext4, including encryption? Also, anyone any thoughts on using live-CD version of Ubuntu for online banking (in case the online unit got owned)? Please remember that I am a complete newbie to Linux. So please remember if you start talking about OpenWTF 0.666.1066 I will have no idea what you're talking about! Not for some months yet, anyway. :) Thanks for your help, Ian (C) Copyright 2016 by Ian Henderson. All rights reserved. Do not pass on my email address without my prior written consent (if emailing multiple recipients at the same time, use the BCC field in place of the To field).

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