Cisco Cisco Expressway
Appendix 3: Firewall and NAT settings
Internal firewall configuration
In many deployments outbound connections (from internal network to DMZ) will be permitted by the
NAT/firewall device. If the administrator wants to restrict this further, the following tables provide the
permissive rules required. For further information, see
NAT/firewall device. If the administrator wants to restrict this further, the following tables provide the
permissive rules required. For further information, see
.
Ensure that any SIP or H.323 ‘fixup’ ALG or awareness functionality is disabled on the NAT firewall – if
enabled this will adversely interfere with the Expressway functionality.
enabled this will adversely interfere with the Expressway functionality.
Outbound (Internal network > DMZ)
Purpose
Source
Dest. Source
IP
Source
port
port
Transport
protocol
protocol
Dest. IP
Dest. port
Management
Management
computer
computer
EXPe As
required
>=1024
TCP
192.0.2.2 80 / 443 / 22 / 23
SNMP
monitoring
monitoring
Management
computer
computer
EXPe As
required
>=1024
UDP
192.0.2.2 161
H.323 traversal calls using Assent
Q.931/H.225
and H.245
and H.245
EXPc
EXPe Any
15000 to
19999
19999
TCP
192.0.2.2 2776
RTP Assent
EXPc
EXPe Any
36002 to
59999 *
59999 *
UDP
192.0.2.2 36000 *
RTCP Assent
EXPc
EXPe Any
36002 to
59999 *
59999 *
UDP
192.0.2.2 36001 *
SIP traversal calls
SIP TCP/TLS
EXPc
EXPe 10.0.0.2
25000 to
29999
29999
TCP
192.0.2.2 Traversal zone
ports, e.g. 7001
RTP Assent
EXPc
EXPe 10.0.0.2
36002 to
59999 *
59999 *
UDP
192.0.2.2 36000 *
RTCP Assent
EXPc
EXPe 10.0.0.2
36002 to
59999 *
59999 *
UDP
192.0.2.2 36001 *
* The default media traversal port range is 36000 to 59999, and is set on the Expressway-C at
Configuration
> Traversal Subzone
. In Large Expressway systems the first 12 ports in the range – 36000 to 36011 by
default – are always reserved for multiplexed traffic. The Expressway-E listens on these ports. You cannot
configure a distinct range of demultiplex listening ports on Large systems: they always use the first 6 pairs in
the media port range. On Small/Medium systems you can explicitly specify which 2 ports listen for
multiplexed RTP/RTCP traffic, on the Expressway-E (
configure a distinct range of demultiplex listening ports on Large systems: they always use the first 6 pairs in
the media port range. On Small/Medium systems you can explicitly specify which 2 ports listen for
multiplexed RTP/RTCP traffic, on the Expressway-E (
Configuration > Traversal > Ports
). If you choose
not to configure a particular pair of ports (Use configured demultiplexing ports = No), then the
Expressway-E will listen on the first pair of ports in the media traversal port range (36000 and 36001 by
default).
Expressway-E will listen on the first pair of ports in the media traversal port range (36000 and 36001 by
default).
Cisco Expressway Basic Configuration Deployment Guide (X8.5)
Page 42 of 56
Appendix 3: Firewall and NAT settings