Cisco IPSec client does not ping (racoon, vpnc). Routing problem?

Question

VPN

The server is racoon ( debian ).
As a client - vpnc ( debian ).
The connection is established, the vpnc client does not ping from the server and other network clients.
At the same time, OS X and iOS clients ping without problems.
racoon config:
cat /etc/racoon/racoon.conf

log notify;
path pre_shared_key "/etc/racoon/psk.txt";
path certificate "/etc/racoon/certs";

listen {
    isakmp 188.226.183.10 [500];
    isakmp_natt 188.226.183.10 [4500];
}

remote anonymous {
    exchange_mode aggressive, main, base;
    mode_cfg on;
    proposal_check obey;
    nat_traversal on;
    generate_policy unique;
    ike_frag on;
    passive on;
    dpd_delay 30;

    proposal {
        lifetime time 28800 sec;
        encryption_algorithm 3des;
        hash_algorithm md5;
        authentication_method xauth_psk_server;
        dh_group 2;
    }
}

sainfo anonymous {
    encryption_algorithm aes, 3des, blowfish;
    authentication_algorithm hmac_sha1, hmac_md5;
    compression_algorithm deflate;
}

mode_cfg {
    auth_source system;
    dns4 8.8.8.8;
    banner "/etc/racoon/motd";
    save_passwd on;
    network4 10.12.0.10;
    netmask4 255.255.255.0;
    pool_size 100;
    pfs_group 2;
}

vpnc config:
$ cat /etc/vpnc/default.conf

IPSec gateway mydomain.com
IPSec ID mygroup
IPSec secret mygroupsecret
IKE Authmode psk
Xauth username username
Xauth password password
NAT Traversal Mode natt

Routing:
$route

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         *               0.0.0.0         U     0      0        0 tun0
10.0.1.0        *               255.255.255.0   U     0      0        0 eth0
10.12.0.0       *               255.255.255.0   U     0      0        0 tun0
mydomain.com        10.0.1.1        255.255.255.255 UGH   0      0        0 eth0

Interface IP addresses:

eth0 10.0.1.100
tun0 10.12.0.10

Ping comes in:
$ tcpdump -i tun0 -qtln icmp

IP 188.226.183.10 > 10.12.0.10: ICMP echo request, id 12062, seq 1, length 64
IP 188.226.183.10 > 10.12.0.10: ICMP echo request, id 12062, seq 2, length 64

Leaves through another interface:
$ tcpdump -i eth0 -qtln icmp

IP 10.12.0.10 > 188.226.183.10: ICMP echo reply, id 12062, seq 94, length 64
IP 10.12.0.10 > 188.226.183.10: ICMP echo reply, id 12062, seq 95, length 64

I think that the answer should also go by tun0 , but I'm a programmer, not a system administrator.
I would be extremely grateful for a solution.
Thank you!

Answer 1

Do you have iptables disabled for sure (or have the necessary rules for disabling masquerading been added to it)? Because, judging by the routing, everything is ok with it.