Android L2TP via NAPT

Hello,

I tried the L2TP of Android referring to following post.
https://community.sophos.com/products/unified-threat-management/astaroorg/f/58/t/53976

More Android Phone was able to be connected fine.
However, a part of phone was failed.
In the failing phone, the career did NAPT.
(When a source port of NAT-T is 4500, the connection is succeeded.)
Even if the phone that can be connected, the communication was failed through NAPT router.

2011:01:31-19:31:46 asgt pluto[3685]: packet from ***.***.***.***:60279: received Vendor ID payload [RFC 3947]
2011:01:31-19:31:46 asgt pluto[3685]: packet from ***.***.***.***:60279: ignoring Vendor ID payload [draft-ietf-ipsec-nat-t-ike-02]
2011:01:31-19:31:46 asgt pluto[3685]: packet from ***.***.***.***:60279: ignoring Vendor ID payload [draft-ietf-ipsec-nat-t-ike-02_n]
2011:01:31-19:31:46 asgt pluto[3685]: packet from ***.***.***.***:60279: ignoring Vendor ID payload [draft-ietf-ipsec-nat-t-ike-00]
2011:01:31-19:31:46 asgt pluto[3685]: packet from ***.***.***.***:60279: ignoring Vendor ID payload [FRAGMENTATION 80000000]
2011:01:31-19:31:46 asgt pluto[3685]: "S_REF_poLirtPiMX_1"[1] ***.***.***.***:60279 #1: responding to Main Mode from unknown peer ***.***.***.***:60279
2011:01:31-19:31:46 asgt pluto[3685]: "S_REF_poLirtPiMX_1"[1] ***.***.***.***:60279 #1: NAT-Traversal: Result using RFC 3947: peer is NATed
2011:01:31-19:31:46 asgt pluto[3685]: "S_REF_poLirtPiMX_1"[1] ***.***.***.***:60279 #1: Peer ID is ID_IPV4_ADDR: '192.168.0.2'
2011:01:31-19:31:46 asgt pluto[3685]: "S_REF_poLirtPiMX_1"[2] ***.***.***.***:60279 #1: deleting connection "S_REF_poLirtPiMX_1" instance with peer ***.***.***.*** {isakmp=#0/ipsec=#0}
2011:01:31-19:31:46 asgt pluto[3685]: | NAT-T: new mapping ***.***.***.***:60279/60280)
2011:01:31-19:31:46 asgt pluto[3685]: "S_REF_poLirtPiMX_1"[2] ***.***.***.***:60280 #1: sent MR3, ISAKMP SA established
2011:01:31-19:31:46 asgt pluto[3685]: "S_REF_poLirtPiMX_1"[2] ***.***.***.***:60280 #1: ignoring informational payload, type IPSEC_INITIAL_CONTACT
2011:01:31-19:31:47 asgt pluto[3685]: "S_REF_poLirtPiMX_0"[1] ***.***.***.***:60280 #2: responding to Quick Mode
2011:01:31-19:31:47 asgt pluto[3685]: "S_REF_poLirtPiMX_0"[1] ***.***.***.***:60280 #2: IPsec SA established {ESP=>0x0ea7c62f 

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