out of memory
if you see these following lines on your screen and your web server’s stop working, you might want to give “df -h” command on your shell and check whether one of your partition usage is up to 100%.
DMA free:12564kB min:16kB low:32kB high:48kB active:0kB inactive:0kB present:16384kB pages_scanned:427 all_unreclaimable? yes
protections[]: 0 0 0
Normal free:912kB min:928kB low:1856kB high:2784kB active:304036kB inactive:569464kB present:901120kB pages_scanned:2705765 all_unreclaimable? yes
protections[]: 0 0 0
HighMem free:112kB min:128kB low:256kB high:384kB active:65404kB inactive:52876kB present:130976kB pages_scanned:215457 all_unreclaimable? yes
protections[]: 0 0 0
DMA: 3*4kB 3*8kB 3*16kB 4*32kB 3*64kB 1*128kB 1*256kB 1*512kB 1*1024kB 1*2048kB
2*4096kB = 12564kB
Normal: 0*4kB 2*8kB 4*16kB 0*32kB 1*64kB 0*128kB 1*256kB 1*512kB 0*1024kB 0*2048kB 0*4096kB = 912kB
HighMem: 0*4kB 4*8kB 1*16kB 0*32kB 1*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 112kB
Swap cache: add 537645, delete 537644, find 29242/31013, race 0+1
0 bounce buffer pages
Free swap: 0kB
262120 pages of RAM
32744 pages of HIGHMEM
3476 reserved pages
9399 pages shared
1 pages swap cached
Out of Memory: Killed process 2280 (httpd).
in-text advertising:good or bad?
if you want to use it in your commercial website, consider it by reading this
asdafdgfgf.com
if your connection suddenly slow and you see “asdafdgfgf.com ” on the status bar (below on the left side) of most browsers in your LAN then it means that one or more of those computers are infected by a trojan which is doing an arp spoofing. causing confusions in your LAN.
you have to find in which computer the trojan’s running, unplug the network cable form it and have it examined by a better antivirus than the one you’re currently using…:)
here’s a way to find it:
login to your router and find information about arp on the network, here’s what i did in my linux router as root :
$ arp -n | grep eth9.86 | grep -v inc
here’s the result :
192.168.173.33 ether 00:16:76:00:4A:ED C eth9.86
192.168.173.77 ether 00:16:76:00:4A:ED C eth9.86
192.168.173.105 ether 00:16:76:00:4A:ED C eth9.86
192.168.173.32 ether 00:16:76:00:4A:ED C eth9.86
192.168.173.35 ether 00:16:76:00:4A:ED C eth9.86
192.168.173.6 ether 00:16:76:00:4A:ED C eth9.86
192.168.173.73 ether 00:16:76:00:4A:ED C eth9.86
192.168.173.110 ether 00:16:76:00:4A:ED C eth9.86
…..and more
we can see that most of the ip’s have 00:16:76:00:4A:ED as the mac address. this is a strong indication that the computer’s doing arp spoofing and is the root of the problem. a normal condition should be like this :
192.168.173.33 ether 00:11:25:6B:6C:9E C eth9.86
192.168.173.77 ether 00:01:6C:9E:4C:A6 C eth9.86
192.168.173.105 ether 00:11:25:6B:63:BC C eth9.86
192.168.173.32 ether 00:11:25:F1:59:4A C eth9.86
192.168.173.35 ether 00:01:6C:9E:63:29 C eth9.86
192.168.173.6 ether 00:15:77:28:75:26 C eth9.86
192.168.173.73 ether 00:50:DA:3A:F5:15 C eth9.86
192.168.173.110 ether 00:16:76:01:86:F2 C eth9.86
192.168.173.2 ether 00:1B:54:ED:B3:C7 C eth9.86
…..and more
more information on this subject can be find at http://www.netoptima.in/arprotect/
quality of allied telesyn switch
most of switches used in my organization are allied telesyn. recently i have a strange experience with our servers at dmz. upload files via ftp is very slow and never completed at all, but the download is fine and normal. i’ve tried sftp too but also had the same problem. slow upload but normal download.
i suspected the problem was on our mikrotik router which using HP desktop. i thought may be it was the LAN card. i even built a new mikrotik router using IBM thinkcenter to replace the HP. but did not have the chance to replace it because i had another thought that it could be the switch allied telesyn AT-FSW716 who caused the problem.
so i took a cross cable, plug it to connect the mikrotik and a server directly, then do ftp again from a computer on LAN zone. the result was very good, upload is very fast as it was the download. so my guess was right that it could be the switch who caused the problem.
so then i took a new switch from our supply, it’s AT-FS750/16 and installed it on the rackmount under the troubled AT-FSW716… move all cables to the new switch and rip off the troubled switch from the rack…. 
test upload and download again, the result was very well… what’s the lesson in this? do not use AT-FSW716 ever again…….
setting up default quota for new vpopmail user
i use vpopmail 5.4.7. we can set default quota for every newly created user by setting up a certain value in /home/vpopmail/etc/vlimits.default. For example, i want every new user to have only 5Mb quota and maximum 500 messages in their inbox. here what to put in vlimits.default:
default_quota 5242880
default_maxmsgcount 500
now everytime we add a new user without -q option, the new user will have 5Mb quota. we can also set quota for an entire domain in vlimits.default, actually the file is self-explanatory…:)
