- Roundtable - muug.ca

RHEL et al. - how to break mkinitrd(8)
by Adam Thompson 08 Jul '11

08 Jul '11

CentOS 5.6 system. Running happily. Applied kernel update, reboot, PANIC - unable to mount root filesystem. (Along with other various weird error messages.) Spent a lot of time deconstructing initrd(4)s. Final root cause of the problem: in fstab(5), I had manually added a swap partition. "mount -a" didn't care, but mkinitrd sure did: I had fstab like this: /dev/sda1 / ext3 defaults 1 1 /dev/sdb1 / swap defaults 0 0 Mkinitrd(8) was tripping over the "/" in field #2 of the swap record, and generating a non-functional /init script in the initrd. Changing the second line to read "/dev/sdb1 swap swap defaults 0 0" fixed the problem. Aside from documenting this for the edification of others, what's the consensus: is this a bug in mkinitrd(8) that should be reported? (i.e. it should do more sanity checks?) -Adam Thompson athompso(a)athompso.net

2 1

Summer Reading (ie. books I mentioned in passing).
by Sean Cody 15 Jun '11

15 Jun '11

Daemon by Daniel Suarez (author is IMHO the Neil Stephenson of the 20[0,1]?'s, 4.1 out of 5 on the Sean-o-meter) Freedom by Daniel Suarez (sequel to above, not an awesome ending but fun) Zero Day by Mark Russinovich (I _really_ respect this guy's technical creds and he's a decent fiction author as well, 3.8 out of 5 on the Sean-o-meter). A couple more 'cyber punk'/'hacker' novels I like...: Permutation City by Greg Egan (3.9 out of 5 on the Sean-o-meter) Altered Carbon by Richard Morgan (if you are sensitive or turned off by vulgarity don't read this... 4.3 out of 5 on the Sean-o-meter, it is the first of a trilogy but stands well on it's own) I hope you've gotten at least something from my talk today and at the very least maybe a suggestion for some casual reading. Have a great summer everyone. As for 'license' of my slides... I don't care... I _personally_ find the concept of licensing digital assets pretentious and ignorant. It would be nice to know if you are using the material or a credit would be nice but I realize that a license doesn't imply people will honour it so I'm happy as it is. Go nuts. If I wasn't... I wouldn't have made it available. -- Sean P.S. If you are on goodreads send me a note.

1 0

Python for Software Design: How to Think Like a Computer Scientist
by Adam Thompson 15 Jun '11

15 Jun '11

http://greenteapress.com/thinkpython/

1 0

Re: [RndTbl] more on email hosting
by Adam Thompson 14 Jun '11

14 Jun '11

True, but only applicable to email you send. Unless you've configured your system to produce delivery and read receipts, it's nearly impossible to prove you read an email. And if you don't have a copy of it, it'll often be impossible to prove it was even ever delivered to your mail server. (Think retention policies for mail server log files, to protect yourself on both ends of this stick.) It's often a safe bet to assume the other techie had adopted a policy of laziness. -Adam Sean Walberg <sean(a)ertw.com> wrote: >I can appreciate Adam's arguments about email and lawsuits, but there's >nothing stopping the recipient of the email from being required to disclose >the email even if you've (virtually) shredded your copy. > >Like many techie solutions, it requires that everyone adopt the same policy >:) > >Sean > >On Tue, Jun 14, 2011 at 10:25 AM, John Lange <john(a)johnlange.ca> wrote: > >> This is a classic techie "argument" where everyone agrees on >> everything except the solution ;) >> >> -- >> John Lange >> www.johnlange.ca >> _______________________________________________ >> Roundtable mailing list >> Roundtable(a)muug.mb.ca >> http://www.muug.mb.ca/mailman/listinfo/roundtable >> > > > >-- >Sean Walberg <sean(a)ertw.com> http://ertw.com/ > >_______________________________________________ >Roundtable mailing list >Roundtable(a)muug.mb.ca >http://www.muug.mb.ca/mailman/listinfo/roundtable

2 1

more on email hosting
by Adam Thompson 14 Jun '11

14 Jun '11

[Sorry, lost the original thread] One other advantage to self-hosting: you can destroy the data, and be certain it’s destroyed. If you have a retention policy (which we all should, although I don’t…) then you can legally (mostly) destroy old data, and what’s been destroyed legally can’t come back to haunt you in court. If your mail is in the cloud, will your ASP honour a discovery request in a timely fashion? Will you be found in contempt of court because *they* can’t deliver the data? (If I’m going to jail, I’d rather it be for something I did, not for something someone else did!) The list of legal issues goes on and on. Yes, most of these will be settled over time, but considering the pace our legal system moves at, it’ll still be a long time before these issues are clear. If the data is under your direct control, sure, you lose a few excuses, but you do know exactly where you stand. -Adam Thompson athompso(a)athompso.net (204) 291-7950 - direct (204) 489-6515 - fax

3 3

Re: [RndTbl] RHEL.
by Adam Thompson 10 Jun '11

10 Jun '11

More precisely, CentOS makes a big deal out of being binary-compatible right down to loading 3rd-party kernel modules correctly. So unless the software you're using needs to see the string "Red Hat" in /etc/issue, or uses the up2date infrastructure, you should be fine using any of RHEL, CentOS, SL, Oracle Unbreakable Linux, Sun's version (can't remember what it's called) etc. -Adam "Gilbert E. Detillieux" <gedetil(a)cs.umanitoba.ca> wrote: >On 2011-06-10 16:05, Sean Cody wrote: >> Excuse my ignorance but is there a nice legal way (that doesn't eat >> my allowance) to obtain RHEL for use in training? > >Not sure if the academic licenses would cover that, unless you're >registered as a student. > >> I know CentOS is 'mostly compatible' but the mostly part gives me >> pause. I need to get up to speed on WebSphere and DB2 whose >> free/express versions support RHEL specifically. > >I think either CentOS or Scientific Linux would be compatible enough for >those purposes. They're supposed to be kernel version and library >version compatible. > >-- >Gilbert E. Detillieux E-mail: <gedetil(a)muug.mb.ca> >Manitoba UNIX User Group Web: http://www.muug.mb.ca/ >PO Box 130 St-Boniface Phone: (204)474-8161 >Winnipeg MB CANADA R2H 3B4 Fax: (204)474-7609 >_______________________________________________ >Roundtable mailing list >Roundtable(a)muug.mb.ca >http://www.muug.mb.ca/mailman/listinfo/roundtable >

2 1

RHEL.
by Sean Cody 10 Jun '11

10 Jun '11

Excuse my ignorance but is there a nice legal way (that doesn't eat my allowance) to obtain RHEL for use in training? I know CentOS is 'mostly compatible' but the mostly part gives me pause. I need to get up to speed on WebSphere and DB2 whose free/express versions support RHEL specifically. Both products have Window support but I'm not going there. :P My plan is to stand up VMs to go through the installs and basic admin. I don't have to be an expert or run services on it but I'd like to at least be conversant. :) -- Sean (mobile)

2 1

Re: [RndTbl] Shaw dropping bounces?
by Adam Thompson 10 Jun '11

10 Jun '11

Mostly agreed on black lists - they've become mostly useless. Not all of them, there are one or two that are still worth considering but only as part of a weighted decision. Why not Shaw business? Price. Shaw provides exactly the same service but they "let" you run (inbound) servers, for about double the price. Oh, sorry, they do alsounblock port 25 outbound. If you don't need that, then why pay the extra? As to why host locally: control, speed, storage, availability, bandwidth, cost. Many organizations can do away with on-site hosting but not all. If I already have a server in place, why also pay for a VPS? Gmail certainly isn't up to handling massive amounts of spam (~10k/day)... -Adam -Adam John Lange <john(a)johnlange.ca> wrote: >Black lists are evil period. Nothing more than internet vigilantism. > >If this is for business why not use a Shaw business account? Those do >not block port 25. > >Or a better question, why host mail locally at all? > >-- >John Lange >www.johnlange.ca >_______________________________________________ >Roundtable mailing list >Roundtable(a)muug.mb.ca >http://www.muug.mb.ca/mailman/listinfo/roundtable >

2 2

Shaw dropping bounces?
by Trevor Cordes 08 Jun '11

08 Jun '11

We just noticed something strange: Shaw's mail server appears to be dropping some bounces. Our setup is, on Shaw cable ISP, running our own mail server, with Shaw's mail server as our smarthost. Our MX is to our own (Shaw dynamic) IP, so we can recieve mail directly. The reason for this messed up config is that Shaw 1-2 years ago started blocking outgoing SMTP, but they don't block incoming SMTP. If you have a similar setup (some of you must), try sending email to: bogususerid(a)valid.domain.com and bogususerid(a)bogusdomain.com (fill in the "bogus*" with something you make up) The 1st (valid domain) one will bounce. The remote mail server (outside of Shaw) will bounce back to you. No problem there. The 2nd (invalid domain) one will not bounce. It will just disappear. My current theory is Shaw's mail server is wanting to bounce the 2nd one but looks up the MX and thinks "hey, this is in my ISP IP space" and "no one there is allowed to run a server" and then dropping it. Any other ideas?

4 3

MUUG Meeting, June 14, 7:30pm -- Practical Security
by gedetil＠cs.umanitoba.ca 07 Jun '11

07 Jun '11

The Manitoba UNIX User Group (MUUG) will be holding its next monthly meeting on Tuesday, June 14. The meeting topic for this month is as follows: Practical Security For our last meeting of the season, Sean Cody will be speaking on Practical Security. The term "security" is thrown around quite readily and its meaning has been diluted to being a product adjective as opposed to a process or mind set. This presentation will go over the basic theory of computer security and will attempt to equip you with the knowledge to properly evaluate computer security, products and mitigation strategies. Before the break, Michael Doob will present an RTFM topic on using top(1) to browse and manage running processes. The group holds its general meetings at 7:30pm on the second Tuesday of every month from September to June. (There are no meetings in July and August.) Meetings are open to the general public; you don't have to be a MUUG member to attend. ********************************************************************** Please note our meeting location: The IBM offices, at 400 Ellice Ave. (between Edmonton and Kennedy). When you arrive, you will have to sign in at the reception desk, and then wait for someone to take you (in groups) to the meeting room. Please try to arrive by about 7:15pm, so the meeting can start promptly at 7:30pm. Don't be late, or you may not get in. (But don't come too early either, since security may not be there to let you in before 7:15 or so.) Non-members may be required to show photo ID at the security desk. Limited parking is available for free on the street, either on Ellice Ave. or on some of the intersecting streets. Indoor parking is also available nearby, at Portage Place, for $5.00 for the evening. Bicycle parking is available in a bike rack under video surveillance located behind the building on Webb Place. ********************************************************************** For more information about MUUG, and its monthly meetings, check out their Web server: http://www.muug.mb.ca/ Help us promote this month's meeting, by putting this poster up on your workplace bulletin board or other suitable public message board: http://www.muug.mb.ca/meetings/MUUGmeeting.pdf -- Gilbert E. Detillieux E-mail: <gedetil(a)muug.mb.ca> Manitoba UNIX User Group Web: http://www.muug.mb.ca/ PO Box 130 St-Boniface Phone: (204)474-8161 Winnipeg MB CANADA R2H 3B4 Fax: (204)474-7609

1 0