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Cisco ONS 15454 DWDM Reference Manual, R8.5
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Chapter 15      Management Network Connectivity
15.7    Open GNE
By default, the proxy server only allows connections to discovered ONS peers and the firewall blocks 
all IP traffic between the GCC network and LAN. You can, however, provision proxy tunnels to allow 
up to 12 additional destinations for SOCKS version 5 connections to non-ONS nodes. You can also 
provision firewall tunnels to allow up to 12 additional destinations for direct IP connectivity between the 
GCC network and LAN. Proxy and firewall tunnels include both a source and destination subnet. The 
connection must originate within the source subnet and terminate within the destination subnet before 
either the SOCKS connection or IP packet flow is allowed. A proxy connection is allowed if the CTC 
client is in a source subnet and the requested destination is in the destination subnet. Firewall tunnels 
allow IP traffic to route between the node Ethernet and pdcc interfaces. An inbound Ethernet packet is 
allowed through the firewall if its source address matches a tunnel source and its destination matches a 
tunnel destination. An inbound pdcc packet is allowed through the firewall if its source address matches 
a tunnel destination and its destination address matches a tunnel source. Tunnels only affect TCP and 
UDP packets.
The availability of proxy and/or firewall tunnels depends on the network access settings of the node:
 • If the node is configured with the proxy server enabled in GNE or ENE mode, you must set up a 
proxy tunnel and/or a firewall tunnel. 
 • If the node is configured with the proxy server enabled in proxy-only mode, you can set up proxy 
tunnels. Firewall tunnels are not allowed.
 • If the node is configured with the proxy server disabled, neither proxy tunnels nor firewall tunnels 
are allowed. 
Figure 15-25 shows an example of a foreign node connected to the GCC network. Proxy and firewall 
tunnels are useful in this example because the GNE would otherwise block IP access between the PC 
and the foreign node.