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New Member

SA520 Ipsec VPN very unstable


We have Cisco SA520 and we want to use VPN to access the office servers from home. We have been able to configure the VPN server on the SA520 however the connection is very unstable.

We use OS X 10.7 lion built-in Cisco compatible VPN clients and this is a typical output of ping from 3G mobile network to a server inside the office network. It works the same way also if I am trying to access from my home ADSL connection so the problem is not the instability of the 3G connection.

How could we start debugging the problem? Are there some debug options in os x vpn to see what is wrong? Just about anything would be helpful.

Best Regards,


Some sample traffic sequeezed:

PING ns.svm ( 56 data bytes

64 bytes from icmp_seq=0 ttl=63 time=98.022 ms

64 bytes from icmp_seq=1 ttl=63 time=76.934 ms

64 bytes from icmp_seq=2 ttl=63 time=278.201 ms

Request timeout for icmp_seq 3

Request timeout for icmp_seq 4

Request timeout for icmp_seq 5




Request timeout for icmp_seq 17

Request timeout for icmp_seq 18

Request timeout for icmp_seq 19

64 bytes from icmp_seq=20 ttl=63 time=369.323 ms

64 bytes from icmp_seq=21 ttl=63 time=118.023 ms

64 bytes from icmp_seq=22 ttl=63 time=96.226 ms

64 bytes from icmp_seq=23 ttl=63 time=87.934 ms




64 bytes from icmp_seq=63 ttl=63 time=68.556 ms

64 bytes from icmp_seq=64 ttl=63 time=928.409 ms

64 bytes from icmp_seq=65 ttl=63 time=116.983 ms

64 bytes from icmp_seq=66 ttl=63 time=85.453 ms

Request timeout for icmp_seq 67

Request timeout for icmp_seq 68

Request timeout for icmp_seq 69




Request timeout for icmp_seq 82

Request timeout for icmp_seq 83

Request timeout for icmp_seq 84

64 bytes from icmp_seq=85 ttl=63 time=63.530 ms

64 bytes from icmp_seq=86 ttl=63 time=389.565 ms

64 bytes from icmp_seq=87 ttl=63 time=82.438 ms




64 bytes from icmp_seq=100 ttl=63 time=96.842 ms

64 bytes from icmp_seq=101 ttl=63 time=76.136 ms

64 bytes from icmp_seq=102 ttl=63 time=94.277 ms

Everyone's tags (6)
New Member

SA520 Ipsec VPN very unstable

Hi Hannu,

     could you please tell me if you resolved this problem and if so, what was the solution?


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