Juniper JUNOS OS 10.4 - RELEASE NOTES REV 6 Release Note page 103

Copyright © 2011, Juniper Networks, Inc.
New Features in Junos OS Release 10.4 for SRX Series Services Gateways and J Series Services Routers
File Transfer Protocol (FTP) is the part of the ALG that handles FTP traffic. The
PORT/PASV requests and corresponding 200/227 responses in FTP are used to
announce the TCP port, which the host listens to for the FTP data connection.
EPRT/EPSV/229 commands are used for these requests and responses. FTP ALG
supports EPRT/EPSV/229 already, but only for IPv4 addresses.
In Junos OS Release 10.4, EPRT/EPSV/229 commands are updated to support both
IPv4 and IPv6 addresses.
[Junos OS CLI Reference, Junos OS Security Configuration Guide]
ICMP ALG for routing, NAT, and NAT-PT—This feature is supported on all SRX Series
and J Series devices. ALGs support Internet Control Message Protocol version 6
(ICMPv6) an integral part of IPv6 that must be fully implemented by every IPv6 node.
The ICMP ALG handles ICMP traffic by monitoring all ICMP messages and then
performing the following actions:
Closes the session
Modifies the payload
In routing mode, the ICMP ALG closes a session if it receives one of the following
message types:
Echo reply (type 129) message
Destination unreachable (type 1) error message
In Network Address Translation (NAT mode), the ICMP ALG performs the following
actions:
Closes the session if it receives an echo reply (type 129) message or a destination
unreachable (type 1) error message
Modifies the identifier or sequence number of the echo request
Retains the original identifier and sequence number for the echo reply
Translates the embedded IPv6 packet for the ICMPv6 error message
In a Network Address Translation-Protocol Translation (NAT-PT) environment, the
ALG performs the following actions:
Closes the session if it receives an echo reply (type 129) message or a destination
unreachable (type 1) error message
Translates an ICMPv4 ping message to an ICMPv6 ping message
Translates an ICMPv6 ping message to an ICMPv4 ping message
Translates an ICMPv4 error message to an ICMPv6 error message and translates its
embedded IPv4 packet to an IPv6 packet
Translates an ICMPv6 error message to an ICMPv4 error message and translates its
embedded IPv6 packet to an IPv4 packet
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