 |
Network |
|||||||||||||||||||||||||||||||||||||
|
|
If you use CommuniGate Pro in a corporate environment, most of your users will connect to the Server from the corporate LAN(s). Use a web browser to open the Settings realm of the CommuniGate Pro WebAdmin Interface, and click the Network link. The LAN IPs page appears.
The LAN IP Addresses table initially contains the addresses the CommuniGate Pro software retrieved from the Server OS configuration. Correct this list to include all LAN (local networks) the CommuniGate Pro Server needs to serve.
Each table line should include either one IP address or an address range - two IP addresses separated with the minus sign: a range includes both IP addresses and all addresses between them.
A comment (separated with the semicolon (;) symbol) the can be placed at the end of a line. A line starting with a semicolon symbol is a comment line.
Usually, you want all mail clients connecting from the LAN addresses to be able to relay mail to any Internet destination, so you will inlcude the LAN addresses into the Client IP Addresses list.
The list of LAN IP Addresses is used to support real-time (voice, video, etc.) communications, so the CommuniGate Pro Server knows which addresses are "not-real" ("local") addresses, i.e. which addresses cannot be contacted directly from the Internet.
CommuniGate Pro can provide SIP and real-time communications for remote clients located behind NAT devices, implementing the far-end NAT traversal functionality.
To detect clients located behind NATs, the Server needs to know which addresses are used on remote networks behind those NATs. Use a web browser to open the Settings realm of the CommuniGate Pro WebAdmin Interface, and click the Network link. Then open NATed IPs page.
If a SIP client sends a request to CommuniGate Pro and the client own network address specified in the request headers is included into the NATed IP Addresses list, while the Server has received this request from a different network address, NOT listed included into the NATed IP Addresses list, the Server decides that this client is behind a NAT.
To allow other users to make incoming calls to a client behind a NAT, the CommuniGate Pro server keeps the "communication hole" between the client and server open by periodically sending dummy packets to that client. Use the Ping NATed Clients setting to specify how often the Server should send those packets.
If your CommuniGate Pro Server is installed on a LAN behind a NAT/Firewall, the NAT/Firewall device should be configured to relay all connections on its communication (POP, SMTP, SIP, etc.) ports to the CommuniGate Pro Server LAN address. Use this setting to specify the IP address your NAT/Firewall "relays" to CommuniGate Pro.
For example, if your CommuniGate Pro Server has the 10.0.1.12 IP address on your LAN, and the NAT/Firewall relays all incoming connections coming to the 77.77.77.77 IP address to the 10.0.1.12 address, specify the 77.77.77.77 IP address in this setting:
CommuniGate Pro supports various real-time communications. Most of those real-time protocols cannot be used via a NAT/Firewall, so CommuniGate Pro can act as "proxy" for those protocols. When a real-time client on a LAN tries to communicate with the a remote system on the Internet, CommuniGate Pro creates a communication port on its own system, and forces the client to connect to that port instead of the remote system port. The CommuniGate Pro communicates with the remote system itself, relaying the data received from the remote system to the client on the LAN and vice versa.
Media Proxy is used when serving real-time clients located behind remote NAT devices.
Server Administrators with the Can Modify Settings access right can modify the Resolver settings. Open the Obscure page in the Settings section of the Server WebAdmin Interface:
The Resolver records in the System Log are marked with the DNR tag.
If a response is not received, the Resolver resends the request, and waits twice longer, if it times out again, it can resend the request again and wait three times longer.
If you have several Domain Name Servers specified, each time the resolver needs to repeat a request, it sends it to the next DNS server in the list.
Note: when a request is an RBL request, the Resolvers sends the same request not more than twice, and both times it uses the same (Initial) response time-out.
If the Custom option is selected, the CommuniGate Pro Server will use the DNS servers addresses listed in the text field next to this pop-up menu.
If no DNS server address is specified, the CommuniGate Pro Server uses the 127.0.0.1 address, trying to connect to a DNS server that can be running on the same computer as the CommuniGate Pro Server.
When a domain name is resolved into IP addresses, the Resolver checks the first address. If this address is listed in the Dummy IP Addresses list, the Resolver returns the "unknown host/domain name" error code. The same check is performed with the results of the DNS MX-search operations.
The Domain Name Resolver uses TCP connections if the server UDP response came back with the "Truncated" flag set. This feature allows the Resolver to retrieve very large records from DNS servers.
