Dnsmasq and the network "pushing" on CentOS

This simple post shows you how tu push networks to your clients using the Dnsmasq DHCP server.

A possible scenario would be, your DHCP server (192.168.0.1) gives you 192.168.0.x address but you also need to reach 172.16.x.x and 10.0.x x networks, for access to (for instance) some VPN resources in your LAN. Those networks are NOT handled by your DHCP server. The quick solution is to make your DHCP server "pushing" that networks. And that is possibile thanks to "121" dhcp-option.

Let's assume our network id may be "vicinet" (you can also miss the network id, of course):

dhcp-option = vicinet, 121, 10.0.0.0/16, 192.16.0.1, 172.16.0.0/16, 192.168.0.1

The format will always be:

dhcp-option = 'id_net', 121, NETWORK, GATEWAY

Handle voip customers with Siproxd on CentOS 5.7

Install Libosip2

cd /usr/local/src
wget http://www.antisip.com/download/exosip2/libosip2-3.5.0.tar.gz
tar xvf libosip2-3.5.0.tar.gz
yum install gcc
cd libosip2-3.5.0
./configure
make
make install
ll /usr/local/lib

Create a new file in /etc/ld.conf.d

echo "/usr/local/lib" > /etc/ld.conf.d/local.conf
ldconfig

Install Siproxd

cd /usr/local/src
wget http://sourceforge.net/projects/siproxd/files/siproxd/0.8.1/siproxd-0.8.1.tar.gz/download
tar xvf siproxd-0.8.1.tar.gz
cd siproxd-0.8.1/
./configure --with-libosip-prefix=/usr/local/lib
make
make install

Do this:

yum remove gcc

Create siproxd user:

useradd -c "Siproxd user" -r -s /bin/nologin siproxd

Basic Siproxd configuration:

vim /etc/siproxd_customer-name.conf

if_inbound = eth0
if_outbound = eth0

sip_listen_port = 5070
daemonize = 0
silence_log = 1
user = siproxd

hosts_allow_reg = 11.22.33.44/16

registration_file = /var/lib/siproxd/siproxd_registrations
autosave_registrations = 300
pid_file = /var/run/siproxd/siproxd.pid

outbound_proxy_host = voip.provider.example.com
outbound_proxy_port = 5060

rtp_proxy_enable = 0
rtp_port_low = 27000
rtp_port_high = 27100
rtp_timeout = 300
rtp_dscp = 46
sip_dscp = 0
rtp_input_dejitter = 0
rtp_output_dejitter = 0
tcp_timeout = 600
tcp_connect_timeout = 500
tcp_keepalive = 20

debug_level = 0x00000000
debug_port = 0

Start siproxd:

/usr/local/sbin/siproxd

Some explanations:
if_inbound/if_outbound - It's the same interface (eth0) because we just have one
hosts_allow_reg - Put here your customer IP (if he has a static one) with the right mask (/16, /24..); you can calculate the mask using a subnet calculator (http://www.subnet-calculator.com)
rtp_proxy_enable = 0 - We just want to proxy the signaling protocol (SIP) not the audio stream (RTP)
outbound_proxy_host - Put here the customer voip provider that you want to connect to

Before setup asterisk, try siproxd configuration using a softphone such as twinkle, ekiga.. It's better a softphone which includes a "Outbound Proxy" field. Twinkle does the trick.

Twinkle example configuration_
User Tab:
User name* = user ID for voip.provider.example.com
Domain* = user ID for voip.provider.example.com
Authentication Name = password for voip.provider.example.com

SIP server Tab:
check on Use Outbound Proxy
Outbound Proxy = your.siproxd.server:5070

If something goes wrong revisit you siproxd configuration running siproxd in debug mode:

/usr/local/sbin/siproxd -c /etc/siproxd_customer-name.conf -d -1 2

NOTE: do different "/etc/siproxd_customer-name.conf" files to give to each siproxd instance you need.


Asterisk trunk configuration
(on the customer PBX)

contact="user ID for voip.provider.example.com"
context=from-trunk
fromuser="user ID for voip.provider.example.com"
outboundproxy="your.siproxd.server:5070"
type=peer
nat=never
host="your.siproxd.server"
port=5070
insecure=very
secret="password for voip.provider.example.com"
username="user ID for voip.provider.example.com"

NOTE: i'm currently still testing this setup. It works pretty fine, but i cant hide some weird behavior with asterisk trunk. For instance, it's easy encounter a voip congestion placing 2 calls one after another. Using siproxd directly with twinkle doesn't. Given this, the trunk works. Any tips will be appreciate