Linux and Unix technical recipes

You can create tar.gz file with the following command.DO NOT ENTER / after the directory name.

tar -cvzf  test.tar.gz test

From the root prompt on your server, invoke the CPAN shell:

# perl -MCPAN -e shell

Once the Perl interpreter has loaded (and been configured), you can install modules with: install MODULENAME.

The first thing you should do is upgrade your CPAN:

cpan> install Bundle::CPAN

Once it is completed, type:

cpan> reload cpan

Now, enter the following command to retrieve all of the required modules:
cpan> install DateTime


Note

Be aware that after freshly installing make / gcc, your perl installation will not necessarily detect it. This means module installation will still fail during the 'make' stage. You may need to invoke the CPAN shell and run the setup routine again, to point to the location of make:
# perl -MCPAN -e shell CPAN
 
cpan> o conf make /usr/bin/make
cpan> o conf commit

Here is the link:

http://www.research.att.com/~ttsweb/tts/demo.php

The following link contains list of TCP and UDP ports:

http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

Opensips is one of the best solution that are present in opensource, it provide you ITSP level services on good hardware box, Single box configure with opensips can supports 5000-10000 calls at time, which it make any teleco to operate with more then 5-10 billion mins per year. Anyone can use it to support their bussiness which is incuring lot of cost due high hardware cost such as iSoftSwitch.

REQUIRMENTS:

1. gcc / suncc / icc : gcc >= 2.9x; 4.[012] recommended (it will work with older version but it might require some options tweaking for best performance)
2. bison or yacc (Berkley yacc)
3. flex
4. GNU make (on Linux this is the standard “make”, on FreeBSD and Solaris is called “gmake”) version >= 3.79.
5. sed and tr (used in the makefiles)
6. GNU tar (”gtar” on Solaris) and gzip if you want “make tar” to work
7. GNU install or BSD install (on Solaris “ginstall”) if you want “make install”, “make bin”, “make sunpkg” to work
8. openssl if you want to compile the TLS support
9. libsctp if you want to compile the SCTP support
10. libmysqlclient & libz (zlib) -libs and devel headers- if you want mysql DB support (the db_mysql module)
11. libpq / postgresql -libs and devel headers- if you want postgres DB support (the db_postgres module)
12. unixodbc -libs and devel headers- if you want unixodbc DB support (the db_unixodbc module)
13. libexpat if you want the jabber gateway support (the jabber module) or the XMPP gateway support
14. libxml2 if you want to use the cpl-c (Call Processing Language) or the presence modules (presence and pua*)
15. libradius-ng -libs and devel headers- if you want to use functionalities with radius support – authentication, accounting, group support, etc
16. unixodbc – libs and devel headers – if you want UNIXODBC support as DB underlayer
17. libxmlrpc-c3 – libs and devel headers – if you want to have XML-RPC support for the Management interface (MI)
18. libperl – libs and devel headers – if you want PERL connector to support perl scripting from you config file (perl module)
19. libsnmp9 – libs and devel headers – if you want SNMP client functionality (SNMP AgentX subagent) for opensips
20. libldap libs and devel headers v2.1 or greater – if you want LDAP support
21. libconfuse and devel headers – if you want to compile the carrierroute module

INSTALLATION

1. cd /usr/src/
2. Download opensips (Opensips 1.5 wget http://opensips.org/pub/opensips/1.5.0/src/opensips-1.5.0-tls_src.tar.gz)
3. tar -xzf  opensips-1.5.0-tls_src.tar.gz
4. make all
5. make install

Introduction

The field of application of a NAT Gateway is in example a private LAN consisting of several PC with an Internet connection with one public IP address.

• The goal is to share the Internet connection among the LAN PCs.
• The problem is that there is only one public IP for outbound traffic.
• The solution is “Network Address Translation” (or NAT for short).

The Gateway (GW) is equipped with two network interfaces. One gets assigned the public IP, the second a private IP (i.e. 192.168.0.1). Every other LAN PCs has it’s own private IP (i.e. 192.168.0.2). If an outbound connection is requested the LAN PC talks to the gateway which masquerades the outbound traffic using the public IP. So every external connection looks like if it is coming from only one PC.

The basic firewalling will prevent all connections from outside with the exception of SSH (port 22) which we leave open for service purposes (i.e.).

System preparation

The following assumes that the gateway has two network interfaces:

• eth0 will be the external and
• eth1 the internal interface.

To use iptables you need to have at least the following kernel components compiled in or as modules

• ip_tables
• ip_conntrack and ip_conntrack_ftp

IP forwarding needs to be active (echo 1 > /proc/sys/net/ipv4/ip_forward</userdefined).

Setup the external interface using the necessary data from your provider (IP and standard gateway). The internal interface (eth1) needs to get a private IP address, like 10.174.254.197. The routing table of the gateway will be set up automatically during network initialization.

Every LAN PC will use the NAT-Gateways internal IP (192.168.0.1 in our example) as standard gateway in its networking setup.

Firewall script

#!/bin/sh ipt=/sbin/iptables extip=192.168.2.243 # replace with your EXTERNAL IP lan=10.174.254.197/27 # your LAN< # start firewall start_firwall { echo “Enabling IP forwarding.” echo 1 > /proc/sys/net/ipv4/ip_forward echo “Enabling iptables firewall.” # default policies $ipt -P INPUT DROP $ipt -P FORWARD DROP # NAT $ipt -t nat -A POSTROUTING -o eth0 -j SNAT –to-source $extip # INPUT chain $ipt -A INPUT -i lo -j ACCEPT $ipt -A INPUT -i eth1 -s $lan -j ACCEPT $ipt -A INPUT -i eth0 -m state –state ESTABLISHED,RELATED -j ACCEPT $ipt -A INPUT -p tcp –destination-port 22 -j ACCEPT # FORWARD chain $ipt -A FORWARD -i eth1 -s $lan -j ACCEPT $ipt -A FORWARD -i eth0 -m state –state ESTABLISHED,RELATED -j ACCEPT } # stop firewall stop_firwall { $ipt -P INPUT DROP $ipt -P OUTPUT DROP $ipt -P FORWARD DROP # allow internal traffic $ipt -A INPUT -i eth1 -j ACCEPT $ipt -A OUTPUT -o eth1 -j ACCEPT } # flushing, removing and zeroing tables
reset_firwall { chains=`cat /proc/net/ip_tables_names` for i in $chains; do $debug $ipt -t $i -F $debug $ipt -t $i -X $debug $ipt -t $i -Z done } case “$1″ in start|restart|reload) reset_firewall start_firewall  ;; stop) reset_firewall stop_firewall  ;; *) echo “Usage: $0 {start|stop|restart|reload}” exit 1  ;; esac exit 0

#!/bin/bash
# get ip
/sbin/ifconfig $1 | grep inet | awk ‘{print $2}’ | sed ‘s/^addr://g’

To get your Internet address if you are behind a NAT:

## The -n option retrieves the Internet IP address

## if you are behind a NAT

if [ "$1" = "-n" ]

then ip=$(lynx -dump http://cfaj.freeshell.org/ipaddr.cgi)

else if=$1 ## specify which interface, e.g. eth0, fxp0

system=$(uname)

case $system in FreeBSD)

sep=”inet “ ;;

Linux) sep=”addr:” ;;

esac temp=$(ifconfig $if)

temp=${temp#*”$sep”}

 ip=${temp%% *}

fi

printf “%s\n” “$ip”

### CFAJ ###

Add the following line on /etc/network/interfaces

up route add -net 172.22.0.0 netmask 255.255.254.0 gw 192.168.15.101 dev eth0 (The connected Hardware interface.)

Now restart the network service by

#/etc/init.d/networking restart

Enable Auto-Reply

Go to users home folder (here we want to create auto-reply for “user” account)

cd /home/user

create .forward file

vi .forward (add the following line)

|/usr/bin/procmail

create .procmailrc

vi .procmailrc (add the following lines)

SHELL=/bin/sh :0 h c * !^FROM_DAEMON * !^X-Loop: user@example.com | (formail -r -I”Precedence:junk” \ -A”X-Loop: user@example.com ” ; \ cat $HOME/message; \ ) | $SENDMAIL -oi -t :0

create a file message-

vi message

hi, I will be leave on ………… (here you add your message which will be sent to the sender during your vacation)

Disable Auto-Reply

Go to users home folder (here we want to remove auto-reply settings of “user” account)

cd /home/user

mv .forward forward

mv .procmailrc procmailrc