X-Git-Url: http://git.grml.org/?a=blobdiff_plain;f=grml_tips;h=1fe0515c882110997d7d75aa84e8c5187b00b062;hb=260058bf14a528851d5ef3b5fd731767d0f37adc;hp=7825e12696d1122b1e1385410392e20820cc4879;hpb=0a837a8c9ca5810894f65498ff15d521da57f579;p=grml-tips.git

diff --git a/grml_tips b/grml_tips
index 7825e12..1fe0515 100644
--- a/grml_tips
+++ b/grml_tips
@@ -2148,7 +2148,7 @@ Restore the backup using unzsplit:
 
 More usage examples: man zsplit + man unzsplit
 -- 
-Measure network performance using ipserf
+Measure network performance using iperf:
 
 Server side:
 % iperf -s -V
@@ -2569,3 +2569,107 @@ UTF-8 at grml / some general information regarding Unicde/UTF-8:
 
   http://wiki.grml.org/doku.php?id=utf8
 -- 
+
+This allows one ssh connection attepmt per minute per source ip, with a initial
+burst of 10.  The available burst is like a counter which is initialised with
+10. Every connection attempt decrements the counter, and every minute where the
+connection limit of one per minute is not overstepped the counter is
+incremented by one.  If the burst counter is exhausted the real rate limit
+comes into play. This gives you 11 connectionattepmts in the first minute
+before blocked for 10minutes.  After 10 minutes block the game restarts.
+
+Hint: you could set the burst value to 5 and the block time to only 5 minutes
+to achive the same average connection rate but with halve the block time.
+
+iptables -A inet_in -p tcp --syn --dport 22 -m hashlimit --hashlimit-name ssh \
+         --hashlimit 1/minute \ --hashlimit-burst 10 --hashlimit-mode srcip   \
+         --hashlimit-htable-expire 600000 -j ACCEPT
+iptables -A inet_in -p tcp --dport 22 -m state --state NEW -j REJECT
+-- 
+Tunnel a specific connection via socat:
+
+On the client:
+% socat TCP4-LISTEN:8003 TCP4:gateway:500
+
+On the gateway:
+# socat TCP4-LISTEN:500,fork TCP4:target:$PORT
+
+Using localhost:8003 on the client uses the tunnel now.
+-- 
+Set date:
+
+# date --set=060916102007
+
+where the bits are month(2)/day(2)/hour(2)/minute(2)/year(4)
+
+Set date using a relative date:
+
+# date -s '+3 mins'
+
+or
+
+# date -s '+tomorrow'
+
+Display a specific relative date:
+
+# date -d '+5 days -2 hours'
+
+Don't forget to set hardware clock via:
+
+# hwlock -w
+-- 
+Booting grml via network / PXE:
+
+Start grml-terminalserver on a system with network access
+and where grml is running:
+
+# grml-terminalserver
+
+Then booting your client(s) via PXE should work without
+any further work.
+-- 
+Debugging SSL communications:
+
+% openssl s_client -connect server.adress:993
+
+or
+
+# ssldump -a -A -H -i eth0
+
+See http://prefetch.net/articles/debuggingssl.html for more details.
+-- 
+Remove bootmanager from MBR:
+
+# lilo -M /dev/hda -s /dev/null
+-- 
+Rewrite grub to MBR:
+
+# mount /mnt/sda1
+# grub-install --recheck --no-floppy --root-directory=/mnt/sda1 /dev/sda
+-- 
+Rewrite lilo to MBR:
+
+# mount /mnt/hda1
+# lilo -r /mnt/hda1
+-- 
+Create screenshot of plain/real console - tty1:
+# fbgrab -c 1 screeni.png
+-- 
+Create screenshot when running X:
+
+% scrot
+
+Tip: use the gkrellshoot plugin when using gkrellm
+-- 
+Redirect all connections to hostA:portA to hostB:portB, where hostA and hostB are
+different networks:
+
+Run the following commands on hostA:
+
+echo 1 > /proc/sys/net/ipv4/ip_forward
+iptables -t nat -A PREROUTING -p tcp --dport portA -j DNAT --to hostB:portB
+iptables -A FORWARD -i eth0 -o eth0 -d hostB -p tcp --dport portB -j ACCEPT
+iptables -A FORWARD -i eth0 -o eth0 -s hostB -p tcp --sport portB -j ACCEPT
+iptables -t nat -A POSTROUTING -p tcp -d hostB --dport portB -j SNAT --to-source hostA
+-- 
+