Discuss

discuss@lists.centos.org

34753 discussions

OT: SysAdmin Stories
by Geoff Galitz 07 Jun '10

07 Jun '10

Hello, I'm compiling a collection of stories from the systems administrator trenches. They can be short or long, funny or about a particularly challenging problem or period, or even something that appeared very technically challenging and ended up being something very simple. Stories which are more political would be ok so long as they do not have an agenda or can be interpreted as a public attack. I can't promise money but I can promise 15 minutes of fame. The stories will be accumulated over the next few months and go into a book about real world experiences of Systems Administrators and Systems Engineers. Some of the material may be used in our training classes, as well. All stories will be duly credited and I'll even buy a beer (or other non-alcoholic beverage) for anyone I ever meet in person. Stories may be edited for grammar or clarity. This book is still in the proposal stage so there is no firm target date, yet. If for some reason the book is not published (just like tech projects, books are sometimes cancelled at the last minute) they will go up on our website. Thanks! -Geoff --------------------------------- Geoff Galitz Blankenheim NRW, Germany http://eifel-consulting.biz http://www.galitz.org/ http://german-way.com/blog/

9 11

Re: [CentOS] OT: SysAdmin Stories
by C R Ritson 07 Jun '10

07 Jun '10

>Date: Sun, 6 Jun 2010 12:19:30 +0200 >From: "Geoff Galitz" <geoff(a)galitz.org> >Subject: [CentOS] OT: SysAdmin Stories > >I'm compiling a collection of stories from the systems administrator >trenches. .... > >Thanks! > >-Geoff > >--------------------------------- >Geoff Galitz >Blankenheim NRW, Germany >http://eifel-consulting.biz >http://www.galitz.org/ >http://german-way.com/blog/ The internet never forgets - it just loses the thread... This request is similar to one a number of years ago, and the result seemed at the time to be worth keeping. Now with the power of google, you might like to search for "The Unofficial Unix Administration Horror Story" thread. The original requests pop up under:- http://groups.google.com/group/comp.unix.admin/search?group=comp.unix.admin… My personal favourite is the one re-posted then by Mark Brader concerning a recovery from "cd ; rm -rf *" as root (and long before the days of root having /root as a home directory). Another anecdote which shows the dangers of creeping featureism runs something like:- Script started on Mon 07 Jun 2010 09:31:20 AM BST # rm -i -r * rm: cannot remove `-i': No such file or directory # Script done on Mon 07 Jun 2010 09:31:40 AM BST This is waiting to bite the admin today who aliases rm to "rm -i" and feels safe from their own finger trouble until they start to rely on this and reach an environment where the alias has not been set. Chris Ritson (Computing Officer and School Safety Officer) Room 707, Claremont Tower, EMAIL: C.R.Ritson(a)ncl.ac.uk School of Computing Science, PHONE: +44 191 222 8175 Newcastle University, FAX : +44 191 222 8232 Newcastle upon Tyne, UK NE1 7RU. WEB : http://www.cs.ncl.ac.uk/

1 0

Centos on Motorola PowerQuicc?
by hadi motamedi 06 Jun '10

06 Jun '10

Dear All Do you have any experience with hardware emulator for Motorola PowerQuicc on MS Windows host (dedicated for centos installation)? Thank you

1 0

help with sendmail closing relay
by Jerry Geis 04 Jun '10

04 Jun '10

I have centos 4.8 i686. It has stock sendmail. see file below. I am getting reports that it is an open relay. I have searched all around and it seems like it should be closed. I have dnl for accept_unresolvable_domains. What can I do to close my sendmail. Thanks, Jerry My sendmail.mc is as follows: --------------------------------- divert(-1)dnl dnl # dnl # This is the sendmail macro config file for m4. If you make changes to dnl # /etc/mail/sendmail.mc, you will need to regenerate the dnl # /etc/mail/sendmail.cf file by confirming that the sendmail-cf package is dnl # installed and then performing a dnl # dnl # make -C /etc/mail dnl # include(`/usr/share/sendmail-cf/m4/cf.m4')dnl VERSIONID(`setup for Red Hat Linux')dnl OSTYPE(`linux')dnl dnl # dnl # default logging level is 9, you might want to set it higher to dnl # debug the configuration dnl # dnl define(`confLOG_LEVEL', `9')dnl dnl # dnl # Uncomment and edit the following line if your outgoing mail needs to dnl # be sent out through an external mail server: dnl # dnl define(`SMART_HOST',`smtp.your.provider') dnl # define(`confDEF_USER_ID',``8:12'')dnl dnl define(`confAUTO_REBUILD')dnl define(`confTO_CONNECT', `1m')dnl define(`confTRY_NULL_MX_LIST',true)dnl define(`confDONT_PROBE_INTERFACES',true)dnl define(`PROCMAIL_MAILER_PATH',`/usr/bin/procmail')dnl define(`ALIAS_FILE', `/etc/aliases')dnl define(`STATUS_FILE', `/var/log/mail/statistics')dnl define(`UUCP_MAILER_MAX', `2000000')dnl define(`confUSERDB_SPEC', `/etc/mail/userdb.db')dnl define(`confPRIVACY_FLAGS', `authwarnings,novrfy,noexpn,restrictqrun')dnl define(`confAUTH_OPTIONS', `A')dnl dnl # dnl # The following allows relaying if the user authenticates, and disallows dnl # plaintext authentication (PLAIN/LOGIN) on non-TLS links dnl # dnl define(`confAUTH_OPTIONS', `A p')dnl dnl # dnl # PLAIN is the preferred plaintext authentication method and used by dnl # Mozilla Mail and Evolution, though Outlook Express and other MUAs do dnl # use LOGIN. Other mechanisms should be used if the connection is not dnl # guaranteed secure. dnl # Please remember that saslauthd needs to be running for AUTH. dnl # dnl TRUST_AUTH_MECH(`EXTERNAL DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl dnl define(`confAUTH_MECHANISMS', `EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl dnl # dnl # Rudimentary information on creating certificates for sendmail TLS: dnl # cd /usr/share/ssl/certs; make sendmail.pem dnl # Complete usage: dnl # make -C /usr/share/ssl/certs usage dnl # dnl define(`confCACERT_PATH',`/usr/share/ssl/certs') dnl define(`confCACERT',`/usr/share/ssl/certs/ca-bundle.crt') dnl define(`confSERVER_CERT',`/usr/share/ssl/certs/sendmail.pem') dnl define(`confSERVER_KEY',`/usr/share/ssl/certs/sendmail.pem') dnl # dnl # This allows sendmail to use a keyfile that is shared with OpenLDAP's dnl # slapd, which requires the file to be readble by group ldap dnl # dnl define(`confDONT_BLAME_SENDMAIL',`groupreadablekeyfile')dnl dnl # dnl define(`confTO_QUEUEWARN', `4h')dnl dnl define(`confTO_QUEUERETURN', `5d')dnl dnl define(`confQUEUE_LA', `12')dnl dnl define(`confREFUSE_LA', `18')dnl define(`confTO_IDENT', `0')dnl dnl FEATURE(delay_checks)dnl FEATURE(`no_default_msa',`dnl')dnl FEATURE(`smrsh',`/usr/sbin/smrsh')dnl FEATURE(`mailertable',`hash -o /etc/mail/mailertable.db')dnl FEATURE(`virtusertable',`hash -o /etc/mail/virtusertable.db')dnl FEATURE(redirect)dnl FEATURE(always_add_domain)dnl FEATURE(use_cw_file)dnl FEATURE(use_ct_file)dnl dnl # dnl # The following limits the number of processes sendmail can fork to accept dnl # incoming messages or process its message queues to 12.) sendmail refuses dnl # to accept connections once it has reached its quota of child processes. dnl # dnl define(`confMAX_DAEMON_CHILDREN', 12)dnl dnl # dnl # Limits the number of new connections per second. This caps the overhead dnl # incurred due to forking new sendmail processes. May be useful against dnl # DoS attacks or barrages of spam. (As mentioned below, a per-IP address dnl # limit would be useful but is not available as an option at this writing.) dnl # dnl define(`confCONNECTION_RATE_THROTTLE', 3)dnl dnl # dnl # The -t option will retry delivery if e.g. the user runs over his quota. dnl # FEATURE(local_procmail,`',`procmail -t -Y -a $h -d $u')dnl FEATURE(`access_db',`hash -T<TMPF> -o /etc/mail/access.db')dnl FEATURE(`blacklist_recipients')dnl dnl # dnl # dnsbl - DNS based Blackhole List/Black List/Rejection list dnl # See http://www.sendmail.org/m4/features.html#dnsbl dnl # FEATURE(`dnsbl', `bl.spamcop.net', `"Spam blocked see: http://spamcop.net/bl.shtml?"$&{client_addr}')dnl FEATURE(`dnsbl', `cbl.abuseat.org', `"Spam blocked see: http://cbl.abuseat.org/lookup.cgi?ip="$&{client_addr}')dnl FEATURE(`dnsbl', `sbl.spamhaus.org', `"Spam blocked see: http://spamhaus.org/query/bl?ip="$&{client_addr}')dnl FEATURE(`dnsbl', `list.dsbl.org', `"Spam blocked see: http://dsbl.org/listing?"$&{client_addr}')dnl dnl # EXPOSED_USER(`root')dnl dnl # dnl # The following causes sendmail to only listen on the IPv4 loopback address dnl # 127.0.0.1 and not on any other network devices. Remove the loopback dnl # address restriction to accept email from the internet or intranet. dnl # dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl dnl # dnl # The following causes sendmail to additionally listen to port 587 for dnl # mail from MUAs that authenticate. Roaming users who can't reach their dnl # preferred sendmail daemon due to port 25 being blocked or redirected find dnl # this useful. dnl # dnl DAEMON_OPTIONS(`Port=submission, Name=MSA, M=Ea')dnl dnl # dnl # The following causes sendmail to additionally listen to port 465, but dnl # starting immediately in TLS mode upon connecting. Port 25 or 587 followed dnl # by STARTTLS is preferred, but roaming clients using Outlook Express can't dnl # do STARTTLS on ports other than 25. Mozilla Mail can ONLY use STARTTLS dnl # and doesn't support the deprecated smtps; Evolution <1.1.1 uses smtps dnl # when SSL is enabled-- STARTTLS support is available in version 1.1.1. dnl # dnl # For this to work your OpenSSL certificates must be configured. dnl # dnl dnl DAEMON_OPTIONS(`Port=smtps, Name=TLSMTA, M=s')dnl dnl # dnl # The following causes sendmail to additionally listen on the IPv6 loopback dnl # device. Remove the loopback address restriction listen to the network. dnl # dnl DAEMON_OPTIONS(`port=smtp,Addr=::1, Name=MTA-v6, Family=inet6')dnl dnl # dnl # enable both ipv6 and ipv4 in sendmail: dnl # dnl DAEMON_OPTIONS(`Name=MTA-v4, Family=inet, Name=MTA-v6, Family=inet6') dnl # dnl # We strongly recommend not accepting unresolvable domains if you want to dnl # protect yourself from spam. However, the laptop and users on computers dnl # that do not have 24x7 DNS do need this. dnl # dnl # dnl FEATURE(`relay_based_on_MX')dnl dnl # dnl # Also accept email sent to "localhost.localdomain" as local email. dnl # LOCAL_DOMAIN(`localhost.localdomain')dnl dnl # dnl # The following example makes mail from this host and any additional dnl # specified domains appear to be sent from mydomain.com dnl # dnl MASQUERADE_AS(`messagenetsystems.com') dnl dnl # dnl # masquerade not just the headers, but the envelope as well dnl # dnl FEATURE(masquerade_envelope) dnl dnl # dnl # masquerade not just @mydomainalias.com, but @*.mydomainalias.com as well dnl # dnl FEATURE(masquerade_entire_domain)dnl dnl # dnl MASQUERADE_DOMAIN(localhost.localdomain)dnl dnl MASQUERADE_DOMAIN(mydomainalias.com)dnl dnl MASQUERADE_DOMAIN(messagenetsystems.com)dnl MAILER(smtp)dnl MAILER(procmail)dnl dnl FEATURE(`accept_unresolvable_domains')

5 4

redundant ldap - client config
by aurfalien＠gmail.com 04 Jun '10

04 Jun '10

Hi all, I have a few ldap servers slaved to a primary via syncrepl, all is well. I've set my clients to auth against a few and there /etc/ldap.conf looks like so; uri ldap://primary.domain.com ldap://secondary.domain.com However when either primary or slaves go down, while the clients can log in, access is very slow, ls of any dir is painful. The /var/log/messages shows several failed attempts to conect to the slaves ldap servers. Whats the proper way to set up redundant ldap on the clients?

4 5

Re: [CentOS] help with sendmail closing relay
by Jerry Geis 04 Jun '10

04 Jun '10

lists-centos wrote: > ok, what's in your /etc/mail/local-host-names, mailertable and > virtusertable files? > > - Richard > > > # local-host-names - include all aliases for your machine here. visualintercom.com unifiedpaging.com pagestation.com messagenetsystems.com mailertable is empty. Jerry

3 6

update from 4.8 to 5.4?
by Robert Tate 04 Jun '10

04 Jun '10

I have searched the list, and don't see this covered or didn't search for the right words. I'm running CentOS 4.8 and have some DVD's for 5.4. I have a lot of customized and additional software installed and would like to avoid starting over with a scratch install. After the upgrade from the DVD I would do a yum upgrade to 5.5. Is this a workable (and safe) thing to do? What should I look out for? I plan to build a clone of the boot disk in case there is a problem so I can swap it back in to the hba1 position (as soon as I find a way to make a clone of a disk with LVM ). Here is some info on the system: [root@hat /]# cat /etc/redhat-release CentOS release 4.8 (Final) [root@hat /]# uname -a Linux hat.rbt.net 2.6.9-89.0.25.ELsmp #1 SMP Thu May 6 12:28:03 EDT 2010 i686 athlon i386 GNU/Linux[root@hat .spamassassin]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VG00-LV00 2.0G 695M 1.2G 37% / /dev/hda1 494M 25M 444M 6% /boot none 1013M 0 1013M 0% /dev/shm /dev/mapper/VG00-LV04 9.9G 5.4G 4.0G 58% /home /dev/mapper/VG00-LV05 1008M 34M 924M 4% /opt /dev/mapper/VG00-LV03 4.0G 41M 3.7G 2% /tmp /dev/mapper/VG00-LV01 7.9G 4.2G 3.4G 56% /usr /dev/mapper/VG00-LV02 4.0G 929M 2.9G 25% /var Thanks in advance for any help with this.... Bob

5 4

Recommendations for a webcam
by Karanbir Singh 04 Jun '10

04 Jun '10

hi, I am looking for recommendations for a webcam that works out of the box( or something that does not need major work getting going ) on CentOS-5. But I also need it to do : Better than 640x480, have the ability to work in low light and stream via vlc. I have a Philips SPC 900nc which looks good on paper, and just works, but its unable to really do better than 320x240 and its low light performance is quite sad. I've also tried using a logitech quick cam 9000 pro. Which suffers about the same fate. It does manage to get upto 640x480, but at a fairly average end result. Recommendations ? - KB

1 0

[FZH] 关于如何得到最新的Fedora 13 命令
by sync 04 Jun '10

04 Jun '10

刚在网上看到可以使用下面的命令来更新到最新的Fedora 13 : root@xxx: yum --releasever=13 upgrade 这个命令我尝试了的确可以的，分享给大家...

4 3

small touchscreen/ side monitor for access control application
by R P Herrold 04 Jun '10

04 Jun '10

A couple months ago there was an inquirant looking for a small, wall mountable monitor to provide an display and input device for entrance control on an area. Think Geek was out of stock on a possible offering, but just came back. I just received this notification of availabity Mimo Mini USB Monitor - 720-S Slider Touch http://www.thinkgeek.com/computing/usb-gadgets/bfa3/ I have no interest in this referral, beyond the hope of later receiving reports of people succeeding (and writing up) their adaptation of such to CentOS -- Russ herrold

2 1

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Discuss