Ugo's Blog

Have you ever wondered "I want to do this command on an BrandX switch, but I can only remember the BrandY way". Since I've been playing with switches from these 3 manufacturers, I was glad to find this document .

Don't forget that the 29th of July will be this year's sysadmin day! http://www.sysadminday.com/

I discovered last week that since RHEL/CentOS 3, the recommended way to generate CSRs or self-signed certificates is the 'genkey' command, provided by the crypto-utils. It allows you to graphically choose the key size, and if you simply want to create a self-signed certificate, just answer no when it asks if you want to send the CSR to a certificate authority. It shows at the beginning the destination of the created files, but I'll give you a hint (if my memory is good...): /etc/pki/tls/private for the key /etc/pki/tls/certs for the certs

I made many good contacts helping & getting help on the MailScanner mailing list. This is where I got to know Michele Neylon from http://www.blacknight.com/. It mostly started when I shipped him Linux cds to Ireland, but don't think it would have been necessary to start by a favour. Recentely, one of my contacts had a problem with their domain name and even tough Michele must be very busy, he took the time to send me some advice pretty quickly. Thanks Michele! By the way, his blog is at http://blog.blacknight.com/

I decided to stop using my own mail server and migrate my accounts to Google Apps. Fairly easy and now I get many features... Website, docs, mail (with good anti-spam/virus system, and gmail webmail interface), etc. The migration was quite easy as I configured Gmail to get email in my inbox via POP3s, so as the MX propagates, I get all my mails in the Gmail account, even if they reached my old server. I copied my sent items folder via IMAPs. I should have done that a long time ago... And I installed Gmail for BlackBerry, so I have my e-mails in a separate interface. Google Apps even manage the abuse@ and postmaster@ addresses!

Everybody in computing know APC, American Power Conversion, and they are probably the #1 seller for UPS (Uninterruptible Power Supply). I like APC's hardware, and I like the chat on their website, but there are a few thigs that bothers me. First, I hate their magazine promotions, . Why? First, have you ever tried entering one of their 100 contests (win an ipod, win an UPS, whatever) or try to download one of their whitepapers? You have to get on the web, put in a code, then answer like a million questions. I've never been patient enough to complete the process. Next, they claim being "Green" and they are still sending me two copies of their magazine, "Currents" at home, and we get 4 at work. They don't provide an easy way to unsubscribe, and they subscribe you in a very subtle way... I can't remember asking to receive that... Well, that is about it.

Here is the method I've used to upgrade OTRS from 2.2 to 2.3 (2.2.7 to 2.3.2, in fact) I did a full backup of my MySQL data. I backed up 2 files, /opt/otrs/Kernel/Config.pm and /opt/otrs/Kernel/Config/Files/ZZZAuto.pm I upgraded the RPM using rpm -Uvhf otrs-2.3.2-01.i386.rpm Then the Database migration: cd /opt/otrs/scripts/ mysql -uotrs -phot perl DBUpdate-to-2.3.pl mysql -uotrs -phot Restarted httpd, MySQL and OTRS service That's it... You can now log in in the new version (2.3)!

Hi, I just learned about the existence of this... an ethical Google . All searches that produce revenues are going to charities. Comments welcome.

BarricadeMX 2.0 is now out! I had the chance to work a lot with it and here is a little review/announcement: New Features (by category): Flexibility Now available in more formats Binaries (yum repository, rpm, FreeBSD package, etc) VMware Appliance (soon) ISO self-install CD (installs CentOS and BarricadeMX 2.0) Combo Tags This allows rules with more than one criteria. Before, you could only say, for example, skip all tests for this IP address. Now you can say, for example, "skip all test for this IP address, then the recipient is user@domain.com". The same can be said for creating more targeted black list entries. Improved spamd support: Can now tag and add headers In the previous version, it could only reject when the SpamAssassin score was above the configured level. Now it is also possible to deliver the message, but adding a tag in the subject or add headers for client-side filtering smtp-delay-checks This feature is very helpful for 2 reasons: Whitelising: In the pre...

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[root@svr~]# vzdump --snapshot 101 /dev/cdrom: open failed: No medium found starting backup for VPS 101 (/vz/private/101) Thu Jul 12 06:53:52 2007 creating backup for VPS 101 failed (0.00 minutes): unable to dump into snapshot (use option --dumpdir) at /usr/bin/vzdump line 450. What is going on? Here is the answer

Situation: - Stock Centos 4 system with OpenVZ kernel + utilities installed. One big /vz partition, using LVM. Trying to make a backup using: vzdump --dumpdir /var/ --snapshot 101 Error message received: Insufficient free extents (1) in volume group VolGroup00: 16 required What does that mean? It means that you don't have enough free space in the VG (Volume Group) to create an LVM snapshot. What is the solution? Reduce the size of one partition, then resize one LV (logical volume). This is easily done if you don't have only one big / partition. I usually always make a separate partition for /var and for /vz. To determine what logical volume needs to be resized, you can use the df -h command. Mine showed: /dev/mapper/VolGroup00-LogVol05 119G 16G 99G 14% /vz To resize it: Make backups of your VM to be sure Stop the vz service (service vz stop) umount /vz e2fsck -f /dev/VolGroup00/LogVol05 Use resize2fs /dev/VolGroup00/LogVol05 110G Use lvresize to r...

I was trying to debug someone by e-mail and I think he was a little "slow". Then I thought, silently: His brain returned "452 4.3.1 Insufficient system resources"

Hi, I have tried FSL 's BarricadeMX software at two of my client's site. This piece of software is a giant step in the battle against spam. What is it? It is an SMTP proxy, which does many, many tests during the SMTP transaction in a very efficient way. If one test fails, it rejects the message with a 5xx SMTP reply, so the sender should be notified. Il also implements Greylisting in a more intelligent manner than most current Greylisting implementations. I installed and configured it for 2 clients which are in a different situation: One is a high-volume, multiple servers setup, and the other is a smaller setup with only 1 scanning server. On the big setup, it allowed this client to stop the delays they were experiencing and the spam-catching rate is a lot higher. It also simplfied management. On the smaller setup, I enabled BarricadeMX's clamd and spamd support. This way, viruses are blocked at the MTA level, and any spam that scores over a defined parameter. In t...

I just thought I should create a new command. Every linux/unix sysadmin knows chmod , to change the permissions on a file, so I thought having a chmood . So for days like today I'd like to use my new command to be slightly more enthusiastic... Yeah, I thought of that by doing a typo when I was trying to do a chmod ...

Hi, I created a tutorial with Wink that shows how to create an SSH tunnel. In this example, I'll be connecting, using ssh, to a host called server.mydomain.com. Through the tunnel, I'll connect to "destinationhost" on port 8080. This can be usefull if destinationhost only allows connection on port 8080 from the server I'm connecting to using SSH. To setup the tunnel, I simply open the SSH connection. When I want to access the web site located at destinationserver.other.com:8080, I simply enter "localhost:8081" in my browser. Here is the wink tutorial . An SSH tunnel can be used for many reasons: Send or read your e-mails using an insecure protocol (POP3/IMAP/SMTP), through an encrypted tunnel Encrypt your HTTP traffic while in an internet cafe, using a tunnel and a proxy (like squid) Access a host that is behind a firewall (as long as you have access via SSH to another host behind this firewall BTW, this may be against the policy of the organization...

Virtualization makes another thing easier: complete, bare-metal backups. With this contributed package ( vzdump ), it is very easy to make backups of complete VE, sometimes with only little distruption. Features: Can send an e-mail when finished Can compress the resulting tarball Can selectively back up individual VE, or just all of them Can use different method to make sure the snapshot is consistent (stop the VE, suspend the VE, LVM snapshot) Restoring is very easy and the VEID can be different than the original Can do differential backup using xdelta (not tested myself)

Set the VE up Install asterisk wget ftp://ftp.digium.com/pub/asterisk/asterisk-1.2-current.tar.gz tar -xzf asterisk-1.2-current.tar.gz cd asterisk-1.2.18/ yum install glibc-devel ncurses-devel gcc openssl-devel zlib-devel make make mpg123 make install make config Edit /usr/sbin/safe_asterisk to comment out the line about TTY 9 Start asterisk Copy asterisk config files (/etc/asterisk/*) Copy moh mp3's (/var/lib/asterisk/mohmp3/) Copy custom sounds (IVR) Copy voicemail directory Get french sounds : wget ftp://ftp.digium.com/pub/telephony/sounds/asterisk-core-sounds-fr-wav-current.tar.gz tar -xzf asterisk-core-sounds-fr-wav-current.tar.gz Use the script "install_french.sh" (must be run in /var/lib/asterisk/sounds/fr) (see below for script) Change DNS records Test! Create backups (with vzdump) install_french script: #!/bin/bash # Script creant des liens symboliques permetannt l'utilisation des fichiers audios plus rapidement # # Clod Patry (removed e-mail address) # Vers...

I strongly recommend this good anti-spam service for anyone who has its own domain: www.lastspam.com