Re: [CentOS] LVM Stripe
Christopher and Ross, Thanks for the tips. I will make some tests using md and check performance. Unfortunately I can't move the data to another LV to setup a new stripe value when a new PV is added. Thanks Lincoln On Mon, Mar 8, 2010 at 10:43 PM, Ross Walker rswwal...@gmail.com wrote: On Mar 8, 2010, at 7:31 PM, Christopher Chan christopher.c...@bradbury.edu.hk wrote: On Tuesday, March 09, 2010 06:40 AM, Lincoln Zuljewic Silva wrote: Hello list, I have a question about LVM. My server has five disks and I will use it to create a LVM environment. I saw in the lvcreate man page that I can use the “-i” option to set the number of disks that I want to stripe the lvols, but this option doesn’t exists in the “lvchange” option (in case I add new disks to the VG). I had in mind: create 10 lvols – “lvcreate -i5 -L 10G MyVG /dev/MyVG/lvol[1-10]” and in the future, add more disks and incre ate the stripe value of the existing lvols. I would recommend md striping over lvm but then lvm is a bit more flexible on that score if you have disks of varying size. What are you using as your physical volumes? I actually like mdraid for raid1s then striping them with LVM for raid10s and it has the added benefit of passing the config to the file system during mkfs so it sets the chunk size and stripe width appropriately. Does anybody knows how to change the parameter “-i of a lvol that already exists? It appears to be fixed at creation time. Kinda hard to let you mess around with stripesize and what not after stuff has been laid out on the platters. Yeah, unfortunately you can't change the interleave of a LV. You need to keep around 20% in reserve so when you add another PV you can create a new LV with the new interleave and then copy or dump/restore from the old LV to the new, delete the old LV, and repeat for the other LVs in the group. Remember to start with your largest to your smallest LVs. -Ross ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos -- Lincoln Zuljewic Silva More contact info.: http://www.system.adm.br/contact.php How often must a question be asked before it’s considered a frequently asked question? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Syslog for chroot-jailed SFTP users?
Each user has their own jail? I solved a similar issue with jail and syslog adding a -a /home/jail/dev/log parameter to syslog startup. From the syslogd man page: -a socket Using this argument you can specify additional sockets from that syslogd has to listen to. This is needed if you're going to let some daemon run within a chroot() environment. You can use up to 19 additional sockets. If your environment needs even more, you have to increase the symbol MAXFUNIX within the syslogd.c source file. An example for a chroot() daemon is described by the people from OpenBSD at http://www.psionic.com/papers/dns.html. Regards Lincoln On Wed, Feb 10, 2010 at 7:08 PM, Sean Carolan scaro...@gmail.com wrote: Maybe one of you can help. We have set up a CentOS server so that each user who logs in via sftp will be jailed in their home directory. Here's the relevant sshd_config: # override default of no subsystems Subsystem sftp internal-sftp -f LOCAL2 -l INFO Match Group sftponly ChrootDirectory /home/%u ForceCommand internal-sftp This actually works great, but none of the activities of sftponly group members is getting logged. The man page for sftp-server says: For logging to work, sftp-server must be able to access /dev/log. Use of sftp-server in a chroot configuation therefore requires that syslogd(8) establish a logging socket inside the chroot directory. How do I establish a logging socket inside the chroot directory, when the chroot directory is different depending on which user is logging in at any given time? I don't want to run separate sockets in every customer's chroot directory, this is not practical. Any ideas? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos -- Lincoln Zuljewic Silva More contact info.: http://www.system.adm.br/contact.php How often must a question be asked before it’s considered a frequently asked question? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] saslauthd attack
I supose that you are using SMTP authentication with SASL. From the log service=smtp...so, in fact, the attack is coming from the SMTP server and not directly to the SASL. I guess that someone is trying to do a brute force attack on the SMTP server. Regards Lincoln On Wed, Feb 10, 2010 at 6:08 PM, John Hinton webmas...@ew3d.com wrote: I'm seeing a lot of activity over the last two days with what looks to be a kiddie script. Mostly trying to access several of our servers with the username anna. All failed... in fact I don't think we have a user anna on any of our servers. Meanwhile... I'm running Sendmail. This pertains to Centos 4 and 5 servers. I'm also running fail2ban on some and Ossec on others. So far, no blocking is being done. When I look at the logs all I find is under messages and here is a sample: Feb 10 05:23:08 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:25 neptune saslauthd[3369]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:58 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:53 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:54 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:55 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:59 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] So, I can't write a rule to block this attack as I can't find any IP address to block. I've looked and googled til my eyes are red and can't find where to set logging in saslauthd or where ever it needs to be set to record the IP address generating these failures. Does anyone have an idea? Also, some may wish to do a grep 'do_auth' on messages to see if this is happening to you. They sometimes come in rapid succession. John Hinton ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos -- Lincoln Zuljewic Silva More contact info.: http://www.system.adm.br/contact.php How often must a question be asked before it’s considered a frequently asked question? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Syslog for chroot-jailed SFTP users?
If you have: /home/username01/[etc,dev,tmp,bin,lib] /home/username02/[etc,dev,tmp,bin,lib] /home/username03/[etc,dev,tmp,bin,lib] /home/username04/[etc,dev,tmp,bin,lib] I believe you will need: syslogd -a /home/username01/dev/log -a /home/username02/dev/log -a /home/username03/dev/log -a /home/username04/dev/log - or something like this. I don't know the syntax for multiples -a... Regards Lincoln On Wed, Feb 10, 2010 at 9:39 PM, Sean Carolan scaro...@gmail.com wrote: I solved a similar issue with jail and syslog adding a -a /home/jail/dev/log parameter to syslog startup. In our environment the chroot jail is /home/username. Does this mean we need a /home/username/dev/log for each and every user? If the daemon is chroot'd to /home/username wouldn't this be the case? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos -- Lincoln Zuljewic Silva More contact info.: http://www.system.adm.br/contact.php How often must a question be asked before it’s considered a frequently asked question? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] how to send mail from console
Look for erros in /var/log/maillog. Do you have sendmail running? On Fri, Jan 15, 2010 at 11:15 AM, Roland Roland r_o_l_a_...@hotmail.com wrote: Hi all, i'm trying to get a script to send me an email whenever a certain condition takes place.. i'm afraid i dont have experience with mail command nor anything else related to sending emails for that matter.. i googled a bit and tried using mutt and mail ... though i do not recieve any email in my inbox... the command im using is the following : mail -s “disk space report” r_o_l_a_...@hotmail.com should i setup a default smtp to use? where can i check for the errors that are taking place? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos -- Lincoln Zuljewic Silva More contact info.: http://www.system.adm.br/contact.php How often must a question be asked before it’s considered a frequently asked question? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Hardening
Take a look at the CIS guide for Red Hat 5: http://www.cisecurity.org/bench_linux.html (you do not need to be registered to download the PDFs). Regards Lincoln On Mon, Dec 28, 2009 at 5:56 PM, Larry Vaden larry.va...@gmail.com wrote: On Mon, Dec 28, 2009 at 1:53 PM, ML mailingli...@mailnewsrss.com wrote: Hi Guys, I would like advice for best practices to secure my linux boxes. Know if I have been hacked, know of security breaches, etc. Can anyone provide advice? http://wiki.centos.org/HowTos/OS_Protection ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos -- Lincoln Zuljewic Silva More contact info.: http://www.system.adm.br/contact.php How often must a question be asked before it’s considered a frequently asked question? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] MAC address generating script
I didn't test it: http://www.perlmonks.org/?node_id=451219 Source: http://www.google.com.br/search?rlz=1C1GGLS_pt-BRBR323BR323ie=UTF-8q=generate+mac+address; On Fri, Oct 23, 2009 at 9:08 PM, Eugeneapolinary Ju eugeneapolinar...@yahoo.com wrote: ust can't find a script that generates a valid MAC address :S Has anyone has one? thank you ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos -- Lincoln Zuljewic Silva More contact info.: http://www.system.adm.br/contact.php How often must a question be asked before it’s considered a frequently asked question? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Console priority
List archive: http://lists.centos.org/pipermail/centos/ On Tue, Oct 20, 2009 at 7:34 PM, Daniel Bird db...@sgul.ac.uk wrote: Hi all, A while back I vaguely remember someone posting a link to documentation on how to prioritise console access (for want of a better expression). For the life of me I can't find it in the archives or via Google; Can anyone provide a URL? Basically, I have a remote server that thrashes (that's my theory at least) occasionally, resulting in the service (httpd/mysql) failing. When its in this state logging on to the console (serial + screen) responds with login timeout. The only way back from this at the moment is a reboot.. If I can prioritize console access somehow and get on to the server I may find a clue as to what's causing it. Cheers Dan ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos -- Lincoln Zuljewic Silva More contact info.: http://www.system.adm.br/contact.php How often must a question be asked before it’s considered a frequently asked question? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
