X-Git-Url: http://git.grml.org/?a=blobdiff_plain;f=grml_tips;h=1fe0515c882110997d7d75aa84e8c5187b00b062;hb=260058bf14a528851d5ef3b5fd731767d0f37adc;hp=21ff86c6e1d2436cabc884ebde564a81178caabd;hpb=0f7d60b21a1cd14b32a84069fa942ad64ab40e8a;p=grml-tips.git diff --git a/grml_tips b/grml_tips index 21ff86c..1fe0515 100644 --- a/grml_tips +++ b/grml_tips @@ -704,9 +704,9 @@ Write back the guessed table: Develop, test and use exploit code with the Metasploit Framework: cd /tmp -wget http://www.metasploit.com/tools/framework-2.7-snapshot.tar.gz -unp framework-2.7-snapshot.tar.gz -cd framework* +wget http://framework-mirrors.metasploit.com/msf/downloader/framework-3.0.tar.gz +unp framework-3.0.tar.gz +cd framework-3.0 ./msfcli -- Useful documentation: @@ -1088,7 +1088,7 @@ EOF See also: http://www.debian.org/releases/stable/i386/apcs04.html.en Avoid all of the above steps - use grml-debootstrap(8) instead! -- -Convert files from Unicode / UTF to ISO: +Convert files from Unicode / UTF-8 to ISO: % iconv -f utf8 -t iso-8859-15 < utffile > isofile @@ -1756,12 +1756,16 @@ Start X and lock console via exiting: % startx 2>~/.xsession-errors &| exit -- -Which process is writing to disk? +Which process is writing to disk and/or causes the disk to spin up? + +First of all use lsof to check what's going on. Does not help? -> # echo 1 > /proc/sys/vm/block_dump -Warning: you must disable syslogd before you do this, or you must -make sure that kernel output is not logged. +The command sets a sysctl to cause the kernel to log all disk +writes. Please notice that there is a lot of data. So please +disable syslogd/syslog-ng before you do this, or you must make +sure that kernel output is not logged. When you're done, disable block dump using: # echo 0 > /proc/sys/vm/block_dump @@ -1769,6 +1773,10 @@ When you're done, disable block dump using: Alternative: laptop-mode-tools provides a tool named lm-profiler (laptop mode profiler) which handles block_dump on its own. + +See: $KERNEL-SOURCE/Documentation/laptop-mode.txt + +Also take a look at event-viewer(8) which is part of grml-debugtools. -- Install initrd via initramfs-tools for currently running kernel: @@ -2069,10 +2077,13 @@ xfs without vol_id: # xfs_admin -l /dev/sda1 reiserfs without vol_id: -# debugreiserfs /dev/sda1 | grep UUID +# debugreiserfs /dev/sda1 | grep -i label + +jfs without vol_id: +# jfs_tune -l /dev/sda1 | grep -i label reiser4 without vol_id: -# debugfs.reiser4 /dev/sda1 | grep uuid +# debugfs.reiser4 /dev/sda1 | grep -i label -- Check filesystem's UUID: @@ -2080,16 +2091,41 @@ generic way: # vol_id -u /dev/sda1 ext2/3 without vol_id: -# dumpe2fs /dev/sda1 | grep UUID +# dumpe2fs /dev/sda1 | grep -i UUID xfs without vol_id: # xfs_admin -u /dev/sda1 reiserfs without vol_id: -# debugreiserfs /dev/sda1 | grep LABEL +# debugreiserfs /dev/sda1 | grep -i UUID reiser4 without vol_id: -# debugfs.reiser4 /dev/sda1 | grep label +# debugfs.reiser4 /dev/sda1 | grep -i UUID +-- +Change a filesystem's LABEL: + +swap: +# mkswap -L $LABEL /dev/sda1 + +ext2/ext3: +# e2label /dev/sda1 $LABEL +# tune2fs -L $LABEL /dev/sda1 + +reiserfs: +# reiserfstune -l $LABEL /dev/sda1 + +jfs: +# jfs_tune -L $LABEL /dev/sda1 + +xfs: +# xfs_admin -L $LABEL /dev/sda1 + +fat/vfat: +# echo 'drive i: file="/dev/sda1"' >> ~/.mtoolsrc +# mlabel -s i:$LABEL + +ntfs: +# ntfslabel $LABEL /dev/sda1 -- Disable pdiffs feature of APT: @@ -2112,7 +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 @@ -2380,17 +2416,6 @@ EOF Start dnsmasq finally: # Restart dnsmasq -- -Find out which process(es) cause the disk to spin up: - -# echo 1 > /proc/sys/vm/block_dump - -The command sets a sysctl to cause the kernel to log all disk -writes. Please notice that there is a lot of data. - -See: $KERNEL-SOURCE/Documentation/laptop-mode.txt - -Also take a look at event-viewer(8). --- Display stats about memory allocations performed by a program: Usage example for 'ls': @@ -2475,7 +2500,11 @@ Configuration options relevant on harddisk installation: # tzconfig which adjusts /etc/timezone and /etc/localtime according - to the provided information. + to the provided information. Running: + + # dpkg-reconfigure tzdata + + might be useful as well. * /etc/default/rcS: set variable UTC according to your needs, whether your system clock is set to UTC (UTC='yes') or @@ -2497,7 +2526,7 @@ Configuration options relevant on harddisk installation: * If you change the time (using 'date --set ...', ntpdate,...) it is worth setting also the hardware clock to the correct time: - # hwclock --hctosys [--utc] + # hwclock --systohc [--utc] Remember to add the --utc -option if the hardware clock is set to UTC! @@ -2521,3 +2550,126 @@ Further information: http://www.debian.org/doc/manuals/system-administrator/ch-sysadmin-time.html http://wiki.debian.org/TimeZoneChanges -- +Recorder shellscript session using script: + +% script -t 2>~/upgrade.time -a ~/upgrade.script +% scriptreplay ~/upgrade.time ~/upgrade.script +-- +Test UTF-8 capabilities of terminal: + +wget http://melkor.dnp.fmph.uniba.sk/~garabik/debian-utf8/download/UTF-8-demo.txt.gz +zcat UTF-8-demo.txt.gz + +or: + +wget http://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt +cat UTF-8-test.txt +-- +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 +-- +