Добрый день.
Регулярно раз в шесть часов падает L2TP/IPSec, в логах видно:
[I] Aug 24 23:04:33 ipsec: 05[IKE] received NAT-T (RFC 3947) vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received draft-ietf-ipsec-nat-t-ike-08 vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received draft-ietf-ipsec-nat-t-ike-07 vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received draft-ietf-ipsec-nat-t-ike-06 vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received draft-ietf-ipsec-nat-t-ike-05 vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received draft-ietf-ipsec-nat-t-ike-04 vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received draft-ietf-ipsec-nat-t-ike-03 vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received draft-ietf-ipsec-nat-t-ike-02 vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received draft-ietf-ipsec-nat-t-ike-02\n vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received draft-ietf-ipsec-nat-t-ike-00 vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received Cisco Unity vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] received DPD vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] W1.X1.Y1.Z1 is initiating a Main Mode IKE_SA
[I] Aug 24 23:04:33 ipsec: 05[CFG] received proposals: IKE:AES_CBC=128/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_2048, IKE:AES_CBC=128/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_2048, IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024
[I] Aug 24 23:04:33 ipsec: 05[CFG] configured proposals: IKE:AES_CBC=256/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1536, IKE:AES_CBC=256/HMAC_SHA1_96/PRF_HMAC_SHA1/ECP_384, IKE:AES_CBC=256/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_2048, IKE:AES_CBC=256/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:AES_CBC=128/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1536, IKE:AES_CBC=128/HMAC_SHA1_96/PRF_HMAC_SHA1/ECP_256, IKE:AES_CBC=128/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_2048, IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1536, IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:AES_CBC=256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_CBC=128/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:3DES_CBC/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024
[I] Aug 24 23:04:33 ipsec: 05[CFG] selected proposal: IKE:AES_CBC=128/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024
[I] Aug 24 23:04:33 ipsec: 05[IKE] sending XAuth vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] sending DPD vendor ID
[I] Aug 24 23:04:33 ipsec: 05[IKE] sending NAT-T (RFC 3947) vendor ID
[I] Aug 24 23:04:33 ipsec: 10[IKE] linked key for crypto map '(unnamed)' is not found, still searching
[I] Aug 24 23:04:33 ipsec: 11[CFG] looking for pre-shared key peer configs matching W2.X2.Y2.Z2...W1.X1.Y1.Z1[W1.X1.Y1.Z1]
[I] Aug 24 23:04:33 ipsec: 11[CFG] selected peer config "L2TP0"
[I] Aug 24 23:04:33 ipsec: 11[IKE] detected reauth of existing IKE_SA, adopting 1 children and 0 virtual IPs
[I] Aug 24 23:04:33 ipsec: 11[IKE] schedule delete of duplicate IKE_SA for peer 'W1.X1.Y1.Z1' due to uniqueness policy and suspected reauthentication
[I] Aug 24 23:04:33 ipsec: 11[IKE] IKE_SA L2TP0[106] established between W2.X2.Y2.Z2[W2.X2.Y2.Z2]...W1.X1.Y1.Z1[W1.X1.Y1.Z1]
[I] Aug 24 23:04:33 ipsec: 11[IKE] scheduling reauthentication in 28767s
[I] Aug 24 23:04:33 ipsec: 11[IKE] maximum IKE_SA lifetime 28787s
[I] Aug 24 23:04:34 ndm: IpSec::CryptoMapInfo: "L2TP0": crypto map active IKE SA: 2, active CHILD SA: 1.
[I] Aug 24 23:04:43 ipsec: 08[IKE] deleting IKE_SA L2TP0[105] between W2.X2.Y2.Z2[W2.X2.Y2.Z2]...W1.X1.Y1.Z1[W1.X1.Y1.Z1]
[I] Aug 24 23:04:43 ipsec: 08[IKE] sending DELETE for IKE_SA L2TP0[105]
[I] Aug 24 23:04:44 ndm: IpSec::CryptoMapInfo: "L2TP0": crypto map active IKE SA: 1, active CHILD SA: 1.
[I] Aug 24 23:06:35 pppd_L2TP0: No response to 3 echo-requests
[I] Aug 24 23:06:35 pppd_L2TP0: Serial link appears to be disconnected.
[I] Aug 24 23:06:35 pppd_L2TP0: Connect time 386.1 minutes.
[I] Aug 24 23:06:35 pppd_L2TP0: Sent 505126 bytes, received 1072468 bytes.
[I] Aug 24 23:06:35 ndm: Network::Interface::Ip: "L2TP0": IP address cleared.
Пожалуйста помогите решить проблему.