Goal
This scenario is targeting the setting up of basic voice services for an institution. We are proposing a solution where the IP PBX is complementary to the PBX of the institution.
The features that we will be explored are:
- authenticated login
- user provisioning
- gateway to the PSTN
- gateway between SIP and ?.323
- local dial plan
- encryption (endpoint-to-endpoint)
- codec support
- handling of both numeric and alpha-numeric addresses
- accounting
- qos
- availability checks
Applicability
- SIP interface with SIP proxy (OpenSER)
- H.323 interface with H.323 gatekeeper (GnuGk)
- SIP to H.323 gateway (Asterisk)
- Radius authentication (FreeRadius, Radiator)
- LDAP identity management infrastructure (OpenLDAP)
- accounting (MySQL)
guide helps you setup a simple, mature and flexible open source SIP server. OpenSER can be used on systems with limitted resources as well as on carrier grade servers, scaling to up to thousands call setups per second.
Applicability
OpenSER includes all major entity of a SIP Network. It is a registrar, location server, proxy server, redirect server, gateway to SMS/XMPP, or advanced VoIP application server.Discussion of the interconnection of the components
Prerequisites (OS, dependencies on other software)
...
- Linux/Unix OS
Installation (OS agnostic)
Read first carefully the INSTALL file, paying especially attention to section 3C) and 3D).
| Info | ||
|---|---|---|
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There are several packages ready to be installed. Packages are available for Debian, Fedora, FreeBSD, Gentoo, NetBSD, OpenBSD, Solaris. |
| Tip | ||
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If you need a newer version. Make packages by typing 'make deb' or 'make rpm' instead of 'make install'. |
...
Configuration (OS agnostic)
OpenSER - The SIP interface
Sample config for a typical OpenSER setup with:
- authentication
- multi-domain handling
- protected from open-relay calls
- loose routing
- ENUM routing
- SIP.edu incoming call resolution
- NAT support
PSTN Gateway - The gateway to the PBX
Cisco Gw
Cisco CallManager
PRI card on a PC with Asterisk
GnuGk
Sample config for interfacing with the H.323 world:
- authentication
- ENUM routing
Asterisk
Radius authentication (FreeRadius, Radiator)
LDAP identity management infrastructure (OpenLDAP)
accounting (MySQL)
OS specific help
...
The configuration is located in /etc/openser. The default configuration is ready for a very simple setup and for some very basic tests. You can already try to register to the SIP server.
Troubleshooting with ngrep
Before you try to register to your SIP server make sure udp and tcp port 5060 are open. Use ngrep for tracing SIP messages on the SIP server. Useful commands are:
| Code Block |
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ngrep port 5060
ngrep -d eth0 port 5060
ngrep -q 'test_user_name'
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| Warning | ||
|---|---|---|
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If you get the following error when registering: <Message too big> then probably your host forwards the SIP Message to itself. So trace on localhost to see if this is the case. If your server has more than one DNS entry, make sure that you have all hostnames in |
Troubleshooting with the xlog module
For debugging purposes, it may be very helpful to use the xlog module, which logs directly with syslog.
Add the following line to the /etc/syslog.conf file:
| Code Block |
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# OpenSER messages
# make sure this spacing is done with tabs, spaces may cause errors
local7.* /var/log/openser
# remove local7 from syslog and messages
*.*;auth,authpriv.none,local7.none -/var/log/syslog
*.=info;*.=notice;*.=warn;\
mail,news.none,local7.none -/var/log/messages
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And add the following line to the openser.cfg:
| Code Block |
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log_facility=LOG_LOCAL7
;Add the xlog module:
loadmodule "/usr/lib/openser/modules/xlog.so"
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It is particular helpful for logging variables. You can add e.g. follwing line at the beginning of the default route.
| Code Block |
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xlog("L_INFO", "request method: [$rm], from URI: [$fu], To URI: [$tu]");
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The full set of variables is available on http://openser.org/docs/pseudo-variables.html
Control server with openserctl
With sudo openserctl moni you can monitor the state of your openser (whether it is actually running after the installation).
openserctl is located in /usr/sbin, which is not by default in the user PATH. To use openserctl as a non-priviledged user you need to add the path to the environment export $PATH=PATH:/usr/sbin or call with the full path /usr/sbin/openserctl. Addionally you have to change permissions for the fifosockets. Add the following line in /etc/openser/openser.cfg.
| Code Block |
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sock_group="staff" # openser socket/fifo group, e.g. staff
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If you don't want to type the read/write password every time you make a change via openserctl, you can add the following lines to your /etc/openser/openserctlrc. This is also a good moment to configure the SIP domain.
| Code Block |
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## password for database read/write user
DBRWPW=openserrw
## your SIP domain
SIP_DOMAIN=yoursipdomain.ch
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| Warning | ||
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Be aware that this can be a security problem, as your password is unencrypted in a file. However, this might be anyway the case in |