EzVPN issues with a Comcast cable connection

Question

I have a problem with a Comcast cable connection and an EzVPN. Simply put the connection drops within minutes of no activity. In other words, if I leave an RDP connection open from my datacenter to the remote site, the VPN connection will stay open all the time. A few minutes after I close the connection the VPN drops and the remote side has to wait until its keys timeout to reconnect (obviously without a reset).
I have multiple sites connecting to the EzVPN server without issues from multiple carriers. This one Comcast connection seems to be an issue. I've verified that the configurations for other DHCP based cable connections and this one are the same (except for local parameters). I've also run PING tests to test reliability and MTU issues. For the reliability I do have 1 - 2 packets out of 200 consistently dropping with a 2 second timeout value for the PING. (This is pinging the next hop router on the connection.) For MTU I was able to PING with packet sizes all the way up to 1500 bytes with the DF bit set.
So, I'm looking for any direction on this issue.
Here is the configuration of the router at the remote site (truncated for clarity):
crypto ipsec df-bit clear
crypto ipsec client ezvpn comcast-remote1
connect auto
group comcast-remote1 key testing1234
mode network-extension
peer 65.x.x.x
xauth userid mode interactive
bridge irb
interface FastEthernet0
description Trunk to LAN network
switchport mode trunk
interface FastEthernet4
description WAN connection
ip address dhcp client-id FastEthernet4
no ip redirects
no ip unreachables
no ip proxy-arp
duplex auto
speed auto
crypto ipsec client ezvpn comcast-remote1
interface Dot11Radio0
no ip address
bridge-group 1
interface Vlan1
description primary LAN connection
no ip address
ip tcp adjust-mss 1452
bridge-group 1
interface BVI1
description Bridged connection for Dot11Radio0 and Vlan1
ip address 10.x.x.x 255.255.255.0
ip helper-address 192.x.x.x
no ip redirects
no ip unreachables
no ip proxy-arp
ip virtual-reassembly
crypto ipsec client ezvpn comcast-remote1 inside
bridge 1 protocol ieee
bridge 1 route ip
This remote router is a Cisco 871W running this image c870-advsecurityk9-mz.124-4.T7.bin. I've checked the other 871W routers that are on a DHCP cable connection and they are also running this image version.
Here is the relevant sections of the hub (EzVPN server) router:
crypto isakmp policy 20
encr aes 256
group 2
crypto isakmp policy 30
encr aes 256
authentication pre-share
group 2
lifetime 28800
crypto isakmp policy 90
encr aes 256
group 2
lifetime 28800
crypto isakmp keepalive 60 10
crypto isakmp nat keepalive 60
crypto isakmp client configuration group comcast-remote1
key testing1234
acl comcast-remote1_networks
save-password
crypto isakmp profile comcast-remote1_isakmpprof_dyncorp
match identity group comcast-remote1
isakmp authorization list comcast-remote1
client configuration address respond
accounting svpn_accounting
keepalive 60 retry 10
crypto ipsec transform-set high_security esp-aes esp-sha-hmac
crypto ipsec df-bit clear
crypto dynamic-map comcast-remote1_dynmap 20
set transform-set high_security
set isakmp-profile comcast-remote1_isakmpprof_dyncorp
reverse-route
crypto map svpn-map 109 ipsec-isakmp dynamic comcast-remote1_dynmap
interface FastEthernet0/0
bandwidth 102400
no ip address
speed 100
full-duplex
no cdp enable
interface FastEthernet0/0.40
encapsulation dot1Q 40
ip address 65.x.x.x 255.255.255.0
no cdp enable
crypto map svpn-map
crypto ipsec fragmentation before-encryption
interface FastEthernet1/0
switchport access vlan 4
bandwidth 102400
duplex full
speed 100
no cdp enable
interface Vlan4
ip address 192.x.x.x 255.255.255.0
ip virtual-reassembly
Thanks,
Mike

Answer 1

in your client class - method go()
you have try catch like this: make changes at 2 places commented below
try {
Socket s = new Socket("localhost", 7000);
// ObjectInputStream fromServer = new ObjectInputStream(s.getInputStream());
fromServer = new ObjectInputStream(s.getInputStream());
// ObjectOutputStream toServer = new ObjectOutputStream(s.getOutputStream());
toServer = new ObjectOutputStream(s.getOutputStream());
threadNum = (Integer) fromServer.readObject();
int i = 0;
System.out.println("Thread number: " + threadNum);
System.out.println("Connected to server");
do {
} while (!disconnect);
fromServer.close();
toServer.close();
System.out.println("Connection is closed");
} catch (Exception err) {
System.out.println(err.getMessage());
}