VPN client cannot receive packets

[Zhi-Qiang Lei]

On Sep 26, 2014, at 12:35 AM, lokadamus at gmx.de wrote:

> On 25.09.2014 16:47, Zhi-Qiang Lei wrote:
> 
>> Hi,
>> 
>> It is my router/firewall with internet connection.
>> 
>> This time I try to list the packets from 8.8.8.8, but there are none.
>> 
>> root at freebsd-7638:~ # tcpdump src 8.8.8.8
>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>> listening on vtnet0, link-type EN10MB (Ethernet), capture size 65535 bytes
>> 
>> Now the question URL is changed.
>> 
>> http://serverfault.com/questions/631260/freebsd-l2tp-vpn-connection-error
>> 
>> Best regards,
>> Zhi-Qiang Lei
>> zhiqiang.lei at gmail.com
>> 
>> On Sep 25, 2014, at 10:20 PM, lokadamus at gmx.de wrote:
>> 
>>> On 25.09.2014 08:48, Zhi-Qiang Lei wrote:
>>> 
>>>> I setup a L2TP/IPsec VPN as this article:
>>>> 
>>>> http://wiki.stocksy.co.uk/wiki/L2TP_VPN_in_FreeBSD
>>>> 
>>>> My problem is that the connected clients cannot receive packets, however, sending is okay.
>>>> 
>>>> Here are the tcpdump results if I tried to ping 8.8.8.8:
>>>> 
>>>> root at freebsd-7638:~ # tcpdump -i vtnet0 icmp
>>>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>>>> listening on vtnet0, link-type EN10MB (Ethernet), capture size 65535 bytes
>>>> 05:55:17.630770 IP 192.168.99.150 > google-public-dns-a.google.com: ICMP echo request, id 36697, seq 0, length 64
>>>> 05:55:18.627825 IP 192.168.99.150 > google-public-dns-a.google.com: ICMP echo request, id 36697, seq 1, length 64
>>>> 05:55:19.624058 IP 192.168.99.150 > google-public-dns-a.google.com: ICMP echo request, id 36697, seq 2, length 64
>>>> 05:55:20.618946 IP 192.168.99.150 > google-public-dns-a.google.com: ICMP echo request, id 36697, seq 3, length 64
>>>> 05:55:21.622551 IP 192.168.99.150 > google-public-dns-a.google.com: ICMP echo request, id 36697, seq 4, length 64
>>>> 
>>>> What could be wrong? And how can I troubleshoot? You may reply on SuperUser if you want, thanks in advance.
>>>> 
>>>> http://superuser.com/questions/816485/cannot-receive-packets
>>>> 
>>>> Best regards,
>>>> Zhi-Qiang Lei
>>>> zhiqiang.lei at gmail.com
>>>> 
>>>> _______________________________________________
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>>>> 
>>> Hi,
>>> 
>>> Is this your router/ firewall with internet connection?
>>> Look with tcpdump for traffic at 8.8.8.8.
>>> So you can see, if traffic comes back or is missing before your vpn system.
>>> 
>>> 
>>> Best regards
>>> 
>> _______________________________________________
>> freebsd-questions at freebsd.org mailing list
>> http://lists.freebsd.org/mailman/listinfo/freebsd-questions
>> To unsubscribe, send any mail to "freebsd-questions-unsubscribe at freebsd.org"
>> 
> Stupid mistake, have you made a vpn connection with google (8.8.8.8) or with another subnet on the other side?
> When you will test you vpn connection you should ping your other side of your vpn connection.
> 
> Best regards,
> 


When I connect to VPN, I can ping the VPN (gateway) server with its IP in VPN. (My IP in VPN is 192.168.99.150)

$ ping 192.168.99.1
PING 192.168.99.1 (192.168.99.1): 56 data bytes
64 bytes from 192.168.99.1: icmp_seq=0 ttl=64 time=441.677 ms
64 bytes from 192.168.99.1: icmp_seq=1 ttl=64 time=361.192 ms
64 bytes from 192.168.99.1: icmp_seq=2 ttl=64 time=281.524 ms
64 bytes from 192.168.99.1: icmp_seq=3 ttl=64 time=300.120 ms
64 bytes from 192.168.99.1: icmp_seq=4 ttl=64 time=430.178 ms

But I cannot ping 8.8.8.8.

$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
Request timeout for icmp_seq 0
Request timeout for icmp_seq 1
Request timeout for icmp_seq 2
Request timeout for icmp_seq 3
Request timeout for icmp_seq 4
Request timeout for icmp_seq 5

When I ping 8.8.8.8, tcpdump on VPN server shows that there is no response from 8.8.8.8. Did I miss something? Thanks.

Best regards,
Zhi-Qiang Lei