davr's questions

I'm running a small mailman-based mailing list on a Linux server, and the only spam posts we seem to get are in russian. They are automatically moderated of course, since they're not subscribed to the list, but it's still a hassle to have to always go in and clear out the moderation queue. Is there any way I can set up a simple filter that based on certain keywords will just junk incoming mails before mailman sees/processes them?

EDIT: Here is a sample mail

Headers:

Return-Path: <[email protected]>
Received: from mail.orinigal.com (mail.orinigal.com [182.18.2.185])
    by xxx(Postfix) with ESMTP id 4DB4314A45
    for <xxxlists.xxx>; Mon, 27 Feb 2012 02:38:32 -0800 (PST)
Date: Mon, 27 Feb 2012 14:39:37 +0400
From: =?Windows-1251?B?z/Du4mXw6ug=?= <[email protected]>
Reply-To: =?Windows-1251?B?z/Du4mXw6ug=?= <[email protected]>
X-Priority: 3 (Normal)
Message-ID: <[email protected]>
To: [email protected] <[email protected]>
Subject: =?Windows-1251?B?w2/yb+Lo7GP/IOog73Bv4uXw6uDs?=
MIME-Version: 1.0
Content-Type: multipart/alternative;
 boundary="----------U77289585814785"

Message:

From: "Пpактикa cиcтeмного упpaвлeния" <[email protected]>
To: [email protected] <[email protected]>
Cc: 
Date: Tue, 28 Feb 2012 20:28:19 +0400
Subject: Инстpументы наведeния пopядкa в бизнесe


1 маpтa, 2012 г.

Инcтрумeнты наведeния пoрядкa
в бизнеce
или прaктика cиcтeмного упpавления


г. Kиeв, ул. Горькoго (Aнтонoвича), 172
бизнeс-центр «Пaлладиум Cити», 8 эт, oф. 817.

Тeл.: (044) 331-шeсть-чeтыре-14, 592-сeмь-пять-64

(snipped)

We have a linux router providing internet connectivity to several PCs. It's currently using shorewall to help make the iptables setup easier. Is there a way I can set it such that any individual host is prevented from using the entire line? I'm thinking setting the limit at 80%: So any one PC can't use more than 80% of bandwidth, thus if someone is downloading/uploading large files, the connection isn't completely overwhelmed.

I have a Linux server I've just set up, debian squeeze, 2.6.32-5-amd64, and over the past week it's rebooted three times, twice in one day. There was no power outage that I am aware of (and it's running on a UPS), and there are no errors in syslog, besides a few to-be-expected ones on bootup to do with clearing out entries in the ext4 journal due to the unclean shutdown.

What steps can I take to determine the cause of the reboots? Is there a way to get it to hang instead of rebooting, so I can copy stack traces or something off the screen? Any way to increase debug messages, or get it to dump things to disk, or something?

I'd like to monitor bandwidth usage of my Linux servers, but there's a catch: traffic between my two servers is not counted against me, only traffic to the internet at large. However, my servers have only a single network interface, and pretty much everything I've tried measures on a per-interface basis. Does anyone know of a tool that can generate bandwidth graphs, while not counting traffic to/from certain IP ranges?

Bonus points if it generates RRD files (I can already graph them easily) and double bonus points if it works with collectd (either configuration of the standard collectd, or a plugin to it).

I've seen this question: How to identify heavy write to disk?

And I've used dstat and atop before...but they don't seem to pinpoint what process is causing disk I/O. For example, from dstat:

dstat -ta --top-bio
----system---- ----total-cpu-usage---- -dsk/total- -net/total- ---paging-- ---system-- ----most-expensive----
     time     |usr sys idl wai hiq siq| read  writ| recv  send|  in   out | int   csw |  block i/o process
14-12 16:16:25| 22   3  49  26   0   0|2324k    0 |  17k 6144B|   0     0 |1324     0 |
14-12 16:16:26| 24   3  30  43   0   0|4960k 8192B|1498B 4322B|   0     0 |1494     0 |wget          0  4096B
14-12 16:16:27| 25   4  38  33   0   0|4612k  548k|5011B   27k|   0     0 |1582     0 |kjournald     0    24k
14-12 16:16:28| 23   3  42  32   0   0|5072k    0 |  24k 4368B|   0     0 |1495     0 |

Notice how high dsk/total is -- between 2 and 5 MB/sec. But then look at 'most expensive' column -- it's only a couple bytes here, a couple KB there, and sometimes even nothing. It's the same sort of thing with 'atop'. Shows high overall disk usage, but low usage from individual processes. I'm running CentOS 5, kernel 2.6.18-53.

Do I need a newer kernel version? Maybe some system config setting somewhere? The 'atop' homepage recommends installing some kernel patches, but I'd rather not go through the hassle of configuring & compiling my own kernel.

Is there such a thing as a H.323 to RTSP gateway? Am I searching for the wrong terms? This site seems to imply that such a thing should already exists, but I cannot find anything at all. My end goal is to connect a Flash applet (via RTMP) on one end to a video conference (which uses H.323) on the other end. I have a RTMP<-->RTSP/RTP gateway, so a RTSP<-->H.323 gateway would allow this solution to work.

Is it possible to have a SSL certificate for access directly to an IP, and not through a hostname? Eg, can I purchase an SSL certificate to make https://1.2.3.4/ work without giving a security warning?

I need to upgrade OpenSSL on my CentOS server to 0.9.8k or higher, however the latest version in the official CentOS repositories is 0.9.8e, much too old. Is there a 3rd party repository I can use that has newer versions of OpenSSL libraries? If not, can someone provide a quick walkthrough of compiling a newer version of OpenSSL for CentOS? I need it to replace the built in version, so the walkthrough would have to explain how to create a CentOS-compatible RPM.

We have a Linux server acting as a router/firewall for our office. Occasionally someone will upload a large file that takes up all our bandwidth. I don't want to implement any complex rules or traffic shaping, but I'm wondering if there is a way to slow down a single connection on the spot? I found tcpnice, but it doesn't slow down the transfers in my testing.

Is there any way to share a directory of files between virtual machines running in OpenVZ? My particular use case is that I want to have a shared YUM cache directory, for when they all need to run updates, so that each virtual machine doesn't have to separately download the files from the server. This will make it quicker & use less bandwidth. I could set something up with NFS or Samba or any standard network file sharing app, but I was hoping there was something quick and easy I could do since they are all running off the same drive anyway.

I have two servers on two different IPs, lets say they are: 1.2.3.4 and 5.6.7.8. In addition, they both run some virtual machines, who all have private IPs 10.0.0.*. Now, these two servers only have a single ethernet interface each. I want to track total internet traffic to/from these machines from the outside world, but I do NOT want to count any traffic between the two machines or between the virtual machines. How would I set up an accounting rule, using either shorewall's accounting configuration, or plain iptables rules, to track this?

Currently, I have no way of knowing how much internet bandwidth I'm using, since when I look at the overall stats, it includes traffic between my two servers.

Ideally of course would be to ask the router, but that's not available right now.

Background: Host OS is Windows Vista. Guest OS is Ubuntu

VMWare can give direct access to a guest OS to a physical disk partition, so say my disk has two partitions, the first is NTFS and has windows on it, and the second is EXT3, obviously not readable from windows. I can then run VMWare, and give Ubuntu access to that second partition, and he can mount it and access all the data and so on.

However, I just converted my disk in windows into a 'Dynamic Disk'...and now VMWare can't see the individual partitions. Instead it just sees a single partition the size of the entire disk.

Is there any way to give the ext3 partition, which is now inside a windows dynamic disk, to the vmware instance? I know of LDM, but that only works when linux has full access to the entire disk, and I just want to give it access to a single partition.

After upgrading disks on our local server, I was using the "Parted Magic" boot disk along with gparted to move & resize an NTFS partition. I believe it uses the 'ntfsresize' tool internally.

However, somewhere around half way through, the power had a minor blip...and I had a heart attack.

I haven't touched or mounted the disk yet, is there any possible way to restart the operation where I left off? Failing that, what's the best way to recover my data?

Everyone always says "Oh yeah, ntfsresize is perfectly safe, as long as you don't have a power outage or something"...am I screwed?

Under Linux, what's a simple way to automatically watch a logfile, and email me if a certain string appears? I have an application that will log certain failures to a logfile, but has no built-in way of sending alerts or executing scripts on failure. I suppose I could rig something up with tail -f and some shell scripts, but I'd rather use an existing maintained tool if it exists.