Blog – Page 60 – TRUEANGLE

TEE . read from standard input and write to standard output and files

commandline session

$stat version.c
  File: `version.c'
  Size: 0         	Blocks: 0          IO Block: 4096   regular empty file
Device: 801h/2049d	Inode: 5415089     Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/ jeffrin)   Gid: ( 1000/ jeffrin)
Access: 2013-01-07 19:05:13.000000000 +0530
Modify: 2013-01-07 21:55:50.000000000 +0530
Change: 2013-01-07 21:55:50.000000000 +0530
 Birth: -
$stat version.c | tee newversion.c
  File: `version.c'
  Size: 0         	Blocks: 0          IO Block: 4096   regular empty file
Device: 801h/2049d	Inode: 5415089     Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/ jeffrin)   Gid: ( 1000/ jeffrin)
Access: 2013-01-07 19:05:13.000000000 +0530
Modify: 2013-01-07 21:55:50.000000000 +0530
Change: 2013-01-07 21:55:50.000000000 +0530
 Birth: -
$cat newversion.c
  File: `version.c'
  Size: 0         	Blocks: 0          IO Block: 4096   regular empty file
Device: 801h/2049d	Inode: 5415089     Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/ jeffrin)   Gid: ( 1000/ jeffrin)
Access: 2013-01-07 19:05:13.000000000 +0530
Modify: 2013-01-07 21:55:50.000000000 +0530
Change: 2013-01-07 21:55:50.000000000 +0530
 Birth: -
$

TCPDUMP . PRINT LESS PROTOCOL INFORMATION . OUTPUT LINES SHORTER

$sudo /usr/sbin/tcpdump -q
tcpdump: WARNING: eth0: no IPv4 address assigned
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 100535 bytes
^C
0 packets captured
0 packets received by filter
0 packets dropped by kernel
$sudo /usr/sbin/tcpdump -q -i wlan0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wlan0, link-type EN10MB (Ethernet), capture size 100535 bytes
22:53:57.772687 IP ubuntu.ftp.heanet.ie.http > debian.local.33649: tcp 1430
22:53:57.772898 IP debian.local.33649 > ubuntu.ftp.heanet.ie.http: tcp 0
^C22:53:57.777681 IP debian.local.51260 > 192.168.0.1.domain: UDP, length 44

3 packets captured
458 packets received by filter
422 packets dropped by kernel
$

UPGRADE A PACKAGE AND IT'S DEPENDENCIES USING APT-GET

root@debian:~# apt-get install $(apt-cache depends gnome-session | grep Depends | sed "s/.*ends: //" | tr 'n' ' ')
Reading package lists... Done
Building dependency tree
Reading state information... Done
gnome-session-bin is already the newest version.
gnome-session-bin set to manually installed.
gnome-session-common is already the newest version.
gnome-session-common set to manually installed.
The following extra packages will be installed:
  gkbd-capplet gnome-shell-common libebook-1.2-13 libecal-1.2-11 libedataserver-1.2-16 libedataserverui-3.0-1 libgjs0b
The following NEW packages will be installed:
  gkbd-capplet
The following packages will be upgraded:
  gnome-settings-daemon gnome-shell gnome-shell-common libebook-1.2-13 libecal-1.2-11 libedataserver-1.2-16
  libedataserverui-3.0-1 libgjs0b
8 upgraded, 1 newly installed, 0 to remove and 1026 not upgraded.
Need to get 958 kB/4,159 kB of archives.
After this operation, 151 kB of additional disk space will be used.
Do you want to continue [Y/n]?
Get:1 ftp://ftp.iitm.ac.in/debian/ sid/main gkbd-capplet amd64 3.4.0.2-1 [14.0 kB]
Get:2 ftp://ftp.iitm.ac.in/debian/ sid/main gnome-shell amd64 3.4.2-4 [280 kB]
Get:3 ftp://ftp.iitm.ac.in/debian/ sid/main gnome-shell-common all 3.4.2-4 [664 kB]
Fetched 958 kB in 4s (194 kB/s)
(Reading database ... 394386 files and directories currently installed.)
Preparing to replace gnome-settings-daemon 3.4.2+git20120925.a4c817-1 (using .../gnome-settings-daemon_3.4.2+git20121218.7c1322-1_amd64.deb) ...
Unpacking replacement gnome-settings-daemon ...
Selecting previously unselected package gkbd-capplet.
Unpacking gkbd-capplet (from .../gkbd-capplet_3.4.0.2-1_amd64.deb) ...
Preparing to replace gnome-shell 3.4.2-2 (using .../gnome-shell_3.4.2-4_amd64.deb) ...
Unpacking replacement gnome-shell ...
Preparing to replace gnome-shell-common 3.4.2-2 (using .../gnome-shell-common_3.4.2-4_all.deb) ...
Unpacking replacement gnome-shell-common ...
Preparing to replace libedataserver-1.2-16 3.4.3-1 (using .../libedataserver-1.2-16_3.4.4-1_amd64.deb) ...
Unpacking replacement libedataserver-1.2-16 ...
Preparing to replace libebook-1.2-13 3.4.3-1 (using .../libebook-1.2-13_3.4.4-1_amd64.deb) ...
Unpacking replacement libebook-1.2-13 ...
Preparing to replace libecal-1.2-11 3.4.3-1 (using .../libecal-1.2-11_3.4.4-1_amd64.deb) ...
Unpacking replacement libecal-1.2-11 ...
Preparing to replace libedataserverui-3.0-1 3.4.3-1 (using .../libedataserverui-3.0-1_3.4.4-1_amd64.deb) ...
Unpacking replacement libedataserverui-3.0-1 ...
Preparing to replace libgjs0b 1.32.0-2 (using .../libgjs0b_1.32.0-4_amd64.deb) ...
Unpacking replacement libgjs0b ...
Processing triggers for libglib2.0-0:amd64 ...
Processing triggers for man-db ...
Processing triggers for hicolor-icon-theme ...
Processing triggers for desktop-file-utils ...
Processing triggers for gnome-menus ...
Setting up gnome-settings-daemon (3.4.2+git20121218.7c1322-1) ...
Setting up gkbd-capplet (3.4.0.2-1) ...
Setting up libedataserver-1.2-16 (3.4.4-1) ...
Setting up libebook-1.2-13 (3.4.4-1) ...
Setting up libecal-1.2-11 (3.4.4-1) ...
Setting up libedataserverui-3.0-1 (3.4.4-1) ...
Setting up libgjs0b (1.32.0-4) ...
Setting up gnome-shell-common (3.4.2-4) ...
Setting up gnome-shell (3.4.2-4) ...
root@debian:~#

GDB BACKTRACE GOOGLE CHROME SEGFAULT

$gdb /opt/google/chrome/google-chrome core
GNU gdb (GDB) 7.4.1-debian
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later 
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
...
"/opt/google/chrome/google-chrome": not in executable format: File format not recognized
[New LWP 5986]
[New LWP 5999]
[New LWP 6000]
[New LWP 6001]
[New LWP 6002]
[New LWP 6003]
[New LWP 6004]
[New LWP 6005]
[New LWP 6007]
[New LWP 6008]
[New LWP 6009]
[New LWP 6010]
[New LWP 6011]
[New LWP 6012]
[New LWP 6013]
[New LWP 6014]
[New LWP 6015]
[New LWP 6016]
[New LWP 6018]
[New LWP 6019]
[New LWP 6020]
[New LWP 6025]
[New LWP 6033]
[New LWP 6034]
[New LWP 6069]
[New LWP 6006]
Core was generated by `/opt/google/chrome/chro'.
Program terminated with signal 11, Segmentation fault.
#0  0x00007f3e29fddfd7 in ?? ()
(gdb) bt
#0  0x00007f3e29fddfd7 in ?? ()
#1  0x00007f3e31532c60 in ?? ()
#2  0x0000000000000007 in ?? ()
#3  0x00007f3e31faa380 in ?? ()
#4  0x000000000000001d in ?? ()
#5  0x00007f3e29fec2c0 in ?? ()
#6  0x00007f3e29fde472 in ?? ()
#7  0x00007f3e31532c60 in ?? ()
#8  0x0000001d7fffffff in ?? ()
#9  0x0000000000000000 in ?? ()
(gdb) frame 1
#1  0x00007f3e31532c60 in ?? ()
(gdb) list
No symbol table is loaded.  Use the "file" command.
(gdb) info locals
No symbol table info available.
(gdb)

Category : Operating System
Sub-Category : Debugging

what is tcp_retrans_collapse – BOOLEAN ?

ABOUT tcp_retrans_collapse

This variable implements a bug in the TCP protocol so it will be able to talk to certain other buggy TCP stacks. Without implementing this bug in the TCP stack, we would be unable to talk to certain printers that has this bug built in. This bug makes the TCP stack try to send bigger packets on retransmission of packets to work around bugs in those printers and other hardware implementations.

This variable takes a boolean value and is normally set to 1, or on. Implementing this bug workaround will not break compatibility from our host to others, but it will make it possible to speak to those printers. In general, it should not be a dangerous workaround, but you may turn it off if you receive weird error messages.

TYPICAL SHELL SESSIONS RELATED
[bash]
$cat /proc/sys/net/ipv4/tcp_retrans_collapse
1
$
[/bash]

[bash]
$pwd
/home/jeffrin/linux-4.15.4
$grep -r "tcp_retrans_collapse" *
Documentation/networking/ip-sysctl.txt:tcp_retrans_collapse – BOOLEAN
include/net/netns/ipv4.h: int sysctl_tcp_retrans_collapse;
kernel/sysctl_binary.c: { CTL_INT, NET_IPV4_TCP_RETRANS_COLLAPSE, "tcp_retrans_collapse" },
net/ipv4/tcp_ipv4.c: net->ipv4.sysctl_tcp_retrans_collapse = 1;
net/ipv4/sysctl_net_ipv4.c: .procname = "tcp_retrans_collapse",
net/ipv4/sysctl_net_ipv4.c: .data = &init_net.ipv4.sysctl_tcp_retrans_collapse,
net/ipv4/tcp_output.c: if (!sock_net(sk)->ipv4.sysctl_tcp_retrans_collapse)
$

[/bash]

tcp_retrans_collapse - BOOLEAN
Bug-to-bug compatibility with some broken printers. On retransmit try to send bigger packets to work
around bugs in certain TCP stacks.

TCP smart Framing, or TCP-SF for short, enables  the Fast Retransmit/Recovery  algorithms even when  the
congestion window  is small.  Without modifying  the  TCP congestion
control based on the additive-increase/multiplicative-decrease paradigm, TCP-SF  adopts  a  novel
segmentation  algorithm:  while Classic TCP  always tries to send  full-sized segments, a TCP-SF  source
adopts  a  more flexible  s  segmentation algorithm to try and always  have a number of in flight s
segments larger than 3 so  as to enable Fast Recovery. We motivate  this  choice by  real  traffic c 
measurements, which indicate  that today's  traffic is is  populated by short-li flows, whose only means
to recover from a packet loss is  by triggering a Retransmission  Timeout. The key idea of  TCP-SF can
be implemented  on top of  any TCP flavor, , from Tahoe to SACK, and  requires modifications s to the
server  TCP stack only, and can be easily  coupled   with  recent  TCP   enhancements.   The
performance of the proposed TCP modification were studied by means  of simulations,  live measurements 
and  an analytical model. In addition,  the analytical model we have devised has a  general scope, making
it a  valid tool for TCP  performance evaluation in  the small  window region. Improvements  are  remark-
able  under  several  buffer management   schemes,  and  maximized   by  byte-oriented schemes.

SOURCE:
TCP Smart Framing: A Segmentation Algorithm
to Reduce TCP Latency
Marco Mellia, Member, IEEE, Michela Meo, Member, IEEE, and Claudio Casetti

LINKS
https://www.frozentux.net/ipsysctl-tutorial/chunkyhtml/tcpvariables.html
https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt

free – Display amount of free and used memory in the system

commandline session

$free -m -c 10 -s 10
             total       used       free     shared    buffers     cached
Mem:          1948       1816        131          0        105        536
-/+ buffers/cache:       1175        773
Swap:         5706         19       5687

             total       used       free     shared    buffers     cached
Mem:          1948       1816        131          0        105        536
-/+ buffers/cache:       1175        773
Swap:         5706         19       5687

             total       used       free     shared    buffers     cached
Mem:          1948       1820        128          0        105        538
-/+ buffers/cache:       1176        772
Swap:         5706         19       5687

             total       used       free     shared    buffers     cached
Mem:          1948       1820        128          0        105        538
-/+ buffers/cache:       1176        772
Swap:         5706         19       5687

             total       used       free     shared    buffers     cached
Mem:          1948       1789        159          0         96        529
-/+ buffers/cache:       1163        785
Swap:         5706         20       5686

             total       used       free     shared    buffers     cached
Mem:          1948       1797        151          0         96        533
-/+ buffers/cache:       1167        780
Swap:         5706         20       5686

             total       used       free     shared    buffers     cached
Mem:          1948       1803        145          0         96        533
-/+ buffers/cache:       1173        775
Swap:         5706         20       5686

             total       used       free     shared    buffers     cached
Mem:          1948       1791        157          0         95        526
-/+ buffers/cache:       1168        780
Swap:         5706         20       5686

             total       used       free     shared    buffers     cached
Mem:          1948       1790        158          0         95        526
-/+ buffers/cache:       1167        780
Swap:         5706         20       5686

             total       used       free     shared    buffers     cached
Mem:          1948       1792        156          0         95        527
-/+ buffers/cache:       1168        780
Swap:         5706         20       5686
$

$free -m -c 10 -s 3
             total       used       free     shared    buffers     cached
Mem:          1948       1778        170          0         88        531
-/+ buffers/cache:       1158        790
Swap:         5706         21       5685

             total       used       free     shared    buffers     cached
Mem:          1948       1778        169          0         88        532
-/+ buffers/cache:       1158        790
Swap:         5706         21       5685

             total       used       free     shared    buffers     cached
Mem:          1948       1778        170          0         88        531
-/+ buffers/cache:       1158        790
Swap:         5706         21       5685

             total       used       free     shared    buffers     cached
Mem:          1948       1781        167          0         88        532
-/+ buffers/cache:       1160        788
Swap:         5706         21       5685

             total       used       free     shared    buffers     cached
Mem:          1948       1781        167          0         88        531
-/+ buffers/cache:       1160        788
Swap:         5706         21       5685

             total       used       free     shared    buffers     cached
Mem:          1948       1781        167          0         88        531
-/+ buffers/cache:       1160        788
Swap:         5706         21       5685

             total       used       free     shared    buffers     cached
Mem:          1948       1681        266          0         88        529
-/+ buffers/cache:       1063        885
Swap:         5706         21       5685

             total       used       free     shared    buffers     cached
Mem:          1948       1683        2100          0         88        533
-/+ buffers/cache:       1061        887
Swap:         5706         21       5685

             total       used       free     shared    buffers     cached
Mem:          1948       1703        244          0         88        533
-/+ buffers/cache:       1081        867
Swap:         5706         21       5685

             total       used       free     shared    buffers     cached
Mem:          1948       1710        238          0         88        534
-/+ buffers/cache:       1086        862
Swap:         5706         21       5685
$

STITCHED TO ANOTHER free

nc – TCP/IP swiss army knife

Commandline Session
$nc -l -p 4444
hello
how are you ?
Happy Hacking
Hey

$nc 127.0.0.1 4444
hello
how are you ?
Happy Hacking
Hey

Note : shell screenshot edited.

xargs AND cd WITH MORE MANIPULATION

ABOUT xargs

xargs is a command on Unix and most Unix-like operating systems used to build and execute commands from standard input. It converts input from standard input into arguments to a command.

Some commands such as grep and awk can take input either as command-line arguments or from the standard input. However, others such as cp and echo can only take input as arguments, which is why xargs is necessary.

TYPICAL SHELL SESSION EXPOSURE
[bash]
$ls shelter/
symmel
$ls shelter/ | xargs cd –
xargs: cd: No such file or directory
$ls shelter/ | xargs sh -c cd –
$pwd
/home/jeffrin
$ls shelter/ | xargs ls
ls: cannot access symmel: No such file or directory
$ls shelter/ | xargs cd
xargs: cd: No such file or directory
$ls shelter/ | xargs sh -c cd
$pwd
/home/jeffrin
$ls shelter/ | xargs `sh -c cd – `
symmel
$pwd
/home/jeffrin
$ls shelter/ | xargs `sh -c cd `
symmel
$ls shelter/ | xargs sh -c cd
$pwd
/home/jeffrin
$ls shelter/ | xargs `sh -c cd` –
xargs: -: No such file or directory
$ls shelter/ | xargs sh -c cd –
$pwd
/home/jeffrin
$cd symmel-code/
$cd ..
$pwd
/home/jeffrin
$cd shelter/symmel/
$ls
Algorithms beautifulwork books config-files Docs https: language ovlfose
art.text bookmark bugs-general debian-howtos firewall kernel linux README
$ls config-files/ | xargs ls
ls: cannot access corporation-style.txt: No such file or directory
ls: cannot access dot-bashrc: No such file or directory
ls: cannot access dot-emacs: No such file or directory
ls: cannot access dot-gitconfig: No such file or directory
ls: cannot access dot-muttrc: No such file or directory
ls: cannot access dot-muttrc-personal: No such file or directory
ls: cannot access dot-procmailrc: No such file or directory
ls: cannot access fullscreen.text: No such file or directory
ls: cannot access git-smtp-yahoo-commands.txt: No such file or directory
ls: cannot access likins-glow.scm: No such file or directory
ls: cannot access minimal-style.sheet.txt: No such file or directory
ls: cannot access regex.txt: No such file or directory
ls: cannot access save: No such file or directory
ls: cannot access scripts: No such file or directory
ls: cannot access sources.list: No such file or directory
README
$cd config-files/ | xargs ls
Algorithms beautifulwork books config-files Docs https: language ovlfose
art.text bookmark bugs-general debian-howtos firewall kernel linux README
$pwd
/home/jeffrin/shelter/symmel
$cd config-files/ | xargs pwd
/home/jeffrin/shelter/symmel
$cd config-files/
$pwd
/home/jeffrin/shelter/symmel/config-files
$cd ..
$pwd
/home/jeffrin/shelter/symmel
$

[/bash]

How to make tcpdump output without address to name conversion ?

ABOUT tcpdump

tcpdump is a common packet analyzer that runs under the command line. It allows the user to display TCP/IP and other packets being transmitted or received over a network to which the computer is attached.[3] Distributed under the BSD license,[4] tcpdump is free software.

Tcpdump works on most Unix-like operating systems: Linux, Solaris, FreeBSD, DragonFly BSD, NetBSD, OpenBSD, OpenWrt, macOS, HP-UX 11i, and AIX. In those systems, tcpdump uses the libpcap library to capture packets. The port of tcpdump for Windows is called WinDump; it uses WinPcap, the Windows port of libpcap

TYPICAL SHELL EXPOSURE OF tcpdump
[bash]
$tcpdump -i wlan0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wlan0, link-type EN10MB (Ethernet), capture size 100535 bytes
22:57:07.2100693 IP pop-star.mail.vip.gq1.yahoo.com.pop3 > debian.local.52114: Flags [.], ack 1661258925, win 122, options [nop,nop,TS val 2173829932 ecr 976272], length 0
22:57:07.268298 IP debian.local.51864 > 192.168.0.1.domain: 46776+ PTR? 100.0.168.192.in-addr.arpa. (44)
22:57:07.313780 IP 192.168.0.1.domain > debian.local.51864: 46776 NXDomain 0/0/0 (44)
22:57:07.415737 IP6 fe80::217:3fff:fed4:5a91.mdns > ff02::fb.mdns: 0 PTR (QM)? 100.0.168.192.in-addr.arpa. (44)
^C22:57:07.415957 IP debian.local.mdns > 224.0.0.251.mdns: 0 PTR (QM)? 100.0.168.192.in-addr.arpa. (44)

5 packets captured
142 packets received by filter
107 packets dropped by kernel
$tcpdump -n -i wlan0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wlan0, link-type EN10MB (Ethernet), capture size 100535 bytes
22:57:22.254749 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [P.], seq 860083963:860084020, ack 1661259730, win 122, options [nop,nop,TS val 2173844920 ecr 979981], length 57
22:57:22.255313 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [.], ack 57, win 12869, options [nop,nop,TS val 980091 ecr 2173844920], length 0
22:57:22.256184 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [P.], seq 1:36, ack 57, win 12870, options [nop,nop,TS val 980092 ecr 2173844920], length 35
22:57:22.294674 IP 82.99.16.155.6667 > 192.168.0.100.60770: Flags [P.], seq 19625001006:1962500836, ack 144138462, win 362, options [nop,nop,TS val 613570724 ecr 975277], length 180
22:57:22.294781 IP 192.168.0.100.60770 > 82.99.16.155.6667: Flags [.], ack 180, win 1315, options [nop,nop,TS val 980101 ecr 613570724], length 0
22:57:22.535975 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], ack 36, win 122, options [nop,nop,TS val 2173845201 ecr 980092], length 0
22:57:22.720623 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [P.], seq 57:99, ack 36, win 122, options [nop,nop,TS val 2173845386 ecr 980092], length 42
22:57:22.726386 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], seq 99:1529, ack 36, win 122, options [nop,nop,TS val 2173845386 ecr 980092], length 1430
22:57:22.726775 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [.], ack 1529, win 12824, options [nop,nop,TS val 980209 ecr 2173845386], length 0
22:57:22.731894 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], seq 1529:2959, ack 36, win 122, options [nop,nop,TS val 2173845386 ecr 980092], length 1430
22:57:22.736723 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], seq 2959:4389, ack 36, win 122, options [nop,nop,TS val 2173845386 ecr 980092], length 1430
22:57:22.737038 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [.], ack 4389, win 12819, options [nop,nop,TS val 980212 ecr 2173845386], length 0
22:57:22.742285 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], seq 4389:5819, ack 36, win 122, options [nop,nop,TS val 2173845386 ecr 980092], length 1430
22:57:22.747851 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], seq 5819:7249, ack 36, win 122, options [nop,nop,TS val 2173845386 ecr 980092], length 1430
22:57:22.748190 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [.], ack 7249, win 12870, options [nop,nop,TS val 980215 ecr 2173845386], length 0
^C
15 packets captured
15 packets received by filter
0 packets dropped by kernel
$tcpdump -n -i wlan0 not port 80
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wlan0, link-type EN10MB (Ethernet), capture size 100535 bytes
23:00:14.805331 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [P.], seq 861355518:861356469, ack 1661268445, win 122, options [nop,nop,TS val 2174017454 ecr 1023161], length 951
23:00:14.844066 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [.], ack 951, win 12870, options [nop,nop,TS val 1023239 ecr 2174017454], length 0
23:00:14.853690 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [P.], seq 1:36, ack 951, win 12870, options [nop,nop,TS val 1023241 ecr 2174017454], length 35
23:00:15.119868 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], ack 36, win 122, options [nop,nop,TS val 2174017773 ecr 1023241], length 0
23:00:15.283763 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [P.], seq 951:1008, ack 36, win 122, options [nop,nop,TS val 2174017936 ecr 1023241], length 57
23:00:15.284105 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [.], ack 1008, win 12869, options [nop,nop,TS val 1023349 ecr 2174017936], length 0
23:00:15.284884 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [P.], seq 36:71, ack 1008, win 12870, options [nop,nop,TS val 1023349 ecr 2174017936], length 35
23:00:15.551697 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], ack 71, win 122, options [nop,nop,TS val 2174018206 ecr 1023349], length 0
23:00:15.745497 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [P.], seq 1008:1050, ack 71, win 122, options [nop,nop,TS val 2174018397 ecr 1023349], length 42
23:00:15.750532 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], seq 1050:2480, ack 71, win 122, options [nop,nop,TS val 2174018397 ecr 1023349], length 1430
23:00:15.750619 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [.], ack 2480, win 12824, options [nop,nop,TS val 10234100 ecr 2174018397], length 0
23:00:15.754352 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], seq 2480:3910, ack 71, win 122, options [nop,nop,TS val 2174018397 ecr 1023349], length 1430
23:00:15.759837 IP 216.39.54.67.110 > 192.168.0.100.52114: Flags [.], seq 3910:5340, ack 71, win 122, options [nop,nop,TS val 2174018397 ecr 1023349], length 1430
23:00:15.760213 IP 192.168.0.100.52114 > 216.39.54.67.110: Flags [.], ack 5340, win 12819, options [nop,nop,TS val 1023468 ecr 2174018397], length 0
^C
14 packets captured
14 packets received by filter
0 packets dropped by kernel
$
[/bash]
TYPICAL RELATED SOURCE EXPOSURE
[c]
struct netdissect_options {
int ndo_bflag; /* print 4 byte ASes in ASDOT notation */
int ndo_eflag; /* print ethernet header */
int ndo_fflag; /* don’t translate "foreign" IP address */
int ndo_Kflag; /* don’t check TCP checksums */
int ndo_nflag; /* leave addresses as numbers */
.
.
.
.
.
.
[/c]
[c]
case ‘n’:
++ndo->ndo_nflag;
break;
[/c]

TYPICAL SOURCE CODE TAKEN FROM DEBIAN SOURCE PACKAGE tcpdump

grep prints the matching lines – First Character ^

$ 4.2.36 7 507---> grep ^S resume.txt
Self Study and Consulting.
Software Engineer.
Sri Ramakrishna Engineering College, 1996-2000
$ 4.2.36 8 508---> grep ^A resume.txt
August 2007 to present.
Address: 12/214C Papali Road Vazhakkala. Kakkanad West.
$ 4.2.36 9 509---> grep ^J resume.txt
July 2005 - June 2007
$ 4.2.36 10 510---> grep ^N resume.txt
Name:Jeffrin Jose
$ 4.2.36 11 511---> cat resume.txt
Name:Jeffrin Jose

E-Mail Address(s):
ahiliation@yahoo.co.in

descriptive phrase: engineer.

IDEOLOGY

Directing passion to path of knowledge and self realisation.

Project Work (B.E)

Developing of a FTP client/server Model With Kerberos support On GNU/Linux.

Experiance.

Project member .
1. GNU source installer.
http://www.gnu.org/software/sourceinstall/

2. Contributor at Linux Kernel
https://github.com/mirrors/linux-2.6/contributors

3. Founder at Beautiful Work
http://www.beautifulwork.org/

Freelance Consultant

[ 2000 - 2002 ]

1. Installing. Debugging .Configuration of GNU/Linux and other free software stack applications.
2. Good understanding of operating systems concepts -- File systems. Networking. Linux kernel.
3. Understanding of Linux source code structure and ability to build patches from sources.
4. Ability to troubleshoot issues without physical access to systems.
5. Ability to read logs and debug information.

February 2004 - June 2005
Worked as a Scientific Assistant at Rajagiri School of Engineering and Technology.

1. Deployment of MOSIX/Openmosix clusters.
2. Deployment of NFS and NIS systems.
3. Deployment of Thin clients with XDMCP support.
4. Deployment of SSH remote administration system.
5. Generation of multiboot environment among windows and UNIX Flavours.
6. Project Guidance for students.
7. Handled an academic Paper on "Multimedia Systems".

July 2005 - June 2007
Self Study and Consulting.

1.Learning in using GNU and other Free Software Tool Chains.

Technical Assistant. Cochin University Of Science And Technology [ For 60 days ].

2. x86 Hardware repair and maintanance.

August 2007 to present.

Software Engineer.
Rajagiri Vidaypeetham Research Center.
Rajagiri School Of Engineering and Technology

1. Deployment and maintanence of Solaris and Active directory Integration.
2. Advanced project lab setup using Debian GNU/Linux and Sun Solaris.
3. Experiance in SunFire V490 administration.
4. Experiance in Sun StorEdge 3300 administration.
5. General Unix support.
6. Manage Podcast servers.
7. Linux Multimedia Development for Podcast.
8. Linux router and firewall development using shorewall.
9. Testing THIN clients by creating NFS ROOT mounts.
10.Deployment Of OpenLDAP PXE NFS TFTP DCHP Enabled Thin Clients.
11.Documentation work using LaTex.
12. Simple Linux Router Development.

Education :

Sri Ramakrishna Engineering College, 1996-2000
Bachelor of Computer Science and Engineering
Bharathiar University.

Personal Details:

DOB 31.12 1976
Landline . +91-484-2423949.
Mobile Phone. 98955804100.
Address: 12/214C Papali Road Vazhakkala. Kakkanad West.
Kerala. India.
industry of previous Employer: Education
areas of expertise: software engineering.
job Level: 5+ years experience

$ 4.2.36 12 512--->