Redirecting packets to and from SafeLinx Server

Packet mapping is a way to redirect data through a mobile network interface (MNI).

To create a packet mapping, right-click the organizational unit (OU) in which you want to add the packet mapping, click Add Resource > Packet Mapping , and then select the packet type.

Packet mapping lets you:
  • Redirect certain types of data packets according to various criteria. The types of packets are TCP, UDP, ICMP, and other.
  • Change specific fields within the packet header
  • Change specific character strings within the packet data

For example, you have a subnet of email application programs running on SafeLinx Clients that is configured to connect to sendmail servers that listen on well-known port 25. An email server is optimized for SafeLinx Clients and is configured to listen on port 9000; port 25 continues to be used by other client applications. Because email uses simple mail transfer protocol (SMTP), a TCP application, you can set up a TCP mapping function on the SafeLinx Server to redirect all outgoing mail packets from port 25 to port 9000.

For all mappings, you can redirect packets:
  • From a single IP address or from a group (subnet) of IP addresses
  • To a single IP address or to a group (subnet) of IP addresses
  • Only when the packet is going to a SafeLinx Client or coming from a SafeLinx Client.
The following table describes more mapping criteria that you can specify according to the type of packet that is received by the Connection Manager:
Filter type Filter criteria
TCP packets

You can qualify the mapping according to the port that is used by the originator or the receiver of the packet.

You can further qualify the mapping by specifying a from-flag and a to-flag in the packet header.

Note: Flags should only be used by protocol experts who require this level of differentiation for a special purpose.
UDP packets You can qualify the mapping according to the port used by the originator or the receiver of the packet.
ICMP packets You can qualify the mapping according to a specific type of ICMP packet. For some specific ICMP packets, you can further qualify according to the code that applies to the packet.
Other packets You can qualify the mapping according to a specific type of IP-protocol. Specify a search for a specific character string within the packet header.