martes, 28 de diciembre de 2004

Mi shell script para tunning/performance de tcp/ip en linux

Evidentemente, estos parametros no a todo el mundo le sirven.
(Y si, se que son muy bestias)

echo "0" > /proc/sys/net/ipv4/tcp_sack
echo "0" > /proc/sys/net/ipv4/tcp_timestamps
echo "3129344 3137536 3145728" > /proc/sys/net/ipv4/tcp_mem
echo "65536 1398080 2796160" > /proc/sys/net/ipv4/tcp_rmem
echo "65536 1398080 2796160" > /proc/sys/net/ipv4/tcp_wmem
echo "163840" > /proc/sys/net/core/optmem_max
echo "1048560" > /proc/sys/net/core/rmem_default
echo "2097136" > /proc/sys/net/core/rmem_max
echo "1048560" > /proc/sys/net/core/wmem_default
echo "2097136" > /proc/sys/net/core/wmem_max

Actualizacion: Wed Dec 29 16:42:04 CET 2004
Más elegante con sysctl (/etc/sysctl.conf):

net.ipv4.tcp_sack = 0
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_mem = 3129344 3137536 3145728
net.ipv4.tcp_rmem = 65536 1398080 2796160
net.ipv4.tcp_wmem = 65536 1398080 2796160
net.core.optmem_max = 163840
net.core.rmem_default = 1048560
net.core.rmem_max = 2097136
net.core.wmem_default = 1048560
net.core.wmem_max = 2097136

###Hardening Linux:

net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.conf.default.log_martians = 1
net.ipv4.conf.all.log_martians = 1
net.ipv4.icmp_ignore_bogus_error_responses = 1
net.ipv4.ip_default_ttl = 64
net.ipv4.tcp_syn_retries = 5
net.ipv4.tcp_max_syn_backlog = 256

# -Thx Crg

jueves, 23 de diciembre de 2004

Deshabilitar icmp mask reply en tru64


http://www.ornl.gov/lists/mailing-lists/tru64-unix-managers/2001/03/msg00473.html

Seria hacer eso mismo, pero para el valor icmp_rejectcodemask

tal y como dice el siguiente post, siguiendo los pasos de este link:

http://h30097.www3.hp.com/docs/internet/TITLE.HTM


In article , "Jimmy Kelley"
jimmy@federated.com writes:
Is there some way to disable responses to ICMP timestamp requests in
Tru64
UNIX v 4.0f?

I checked the source code; there is indeed a way, although it takes a little
explanation.

There's a kernel global variable (in 4.0F; I'm not sure about earlier releases)
called "icmp_rejectcodemask". This is a bit mask, where each bit corresponds
to an ICMP message type code. If a bit is set, incoming messages with the
corresponding type are not handled by the ICMP protocol code (although they
ARE passed along to the raw-IP input code).

You can set multiple bits, to disable multiple ICMP types.

To disable responses to ICMP timestamp requests, for example, in C the
appropriate assignment would be:

icmp_rejectcodemask |= (1<<ICMP_TSTAMP);

Looking in /usr/include/netinet/ip_icmp.h, we find

#define ICMP_TSTAMP 13 /* timestamp request
*/

and (1<<13) = 8192.

So, to disable responses to ICMP_TIMESTAMP, you would set
icmp_rejectcodemask = 8192.


Currently, the only way to change this variable (so far as I know) is via dbx;
instructions are at http://www.unix.digital.com/internet/tuning.htm#mod_atts

I was told by the kernel engineers that "we are adding this to the on-line
internet server tuning guide for the next revision. It keeps coming up lately."

-Jeff

lunes, 13 de diciembre de 2004

Control del ancho de banda (bandwith/vnstat)

Otra cosa que olvido siempre es el nombre del programita este para controlar el ancho de banda. Es muy sencillo y para ver de un vistazo el bandwith consumido me parece practico. Se llama vnStat. En su pagina web
hay 'screenshots' y todo lo necesario.


Actualizacion: Mon Dec 13 18:25:02 CET 2004
DS se ha currado un rpm para fc3:

spezialk.net


miércoles, 1 de diciembre de 2004

Sincronizar Palm con HotSync e irda

Si estas tratando de sincronizar tu palm con el portatil
y te da un error al marcar la opcion de infrarojos
en el hotsync (mandandote a leer //Helpnotes//IR_Readme.txt)
algo asi como: "Error accessing the IR Port. See the
//Helpnotes//IR_Readme.txt for more information", tiene facil
solucion:

- Panel de control
- Wireless link
- En la pestaña de Wireless Link desmarcar la opcion:
"Use wireless link to transfer images from a digital
camera to your computer".
(En castellano no se como lo pondra)
- Una vez hecho esto, rearrancar el hotsync y arreando.

No olvidar marcar en la pda que vais a usar irda!