I have an OpenVPN 2.4 installed in Ubuntu 16.04 configured in full tunnel server mode(push "redirect-gateway def1 bypass-dhcp"). Clients are able to connect and use the VPN service fine, however there is an initial delay of 30 seconds for messages in WhatsApp to be delivered after connection or calls to start working. After this delay, its working fine. I am using OpenVPN for Android as client. I guess this has something to do at the TCP level, due to keepalive. Saw these messages in server logs:
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MULTI: bad source address from client [xx.xx.xx.xx], packet dropped
So I added iroute and it fixed the problem. But I don't want to add iroutes since there is only 1 client(duplicate-cn) and the iroute will be pushed to all clients. Also, we need to add iroutes dynamically prior to client connection which is not easy.
This is my server configuration:
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ifconfig-pool-persist ipp.txt
log-append /etc/openvpn/server.log
status /etc/openvpn/status 10
status-version 2
persist-key
persist-tun
user root
group root
ca ca.crt
cert server.crt
key server.key
dh dh2048.pem
tls-auth ta.key 0
server 10.108.0.0 255.255.0.0
duplicate-cn
push "dhcp-option DNS 208.67.222.222"
push "dhcp-option DNS 208.67.220.220"
push "redirect-gateway def1 bypass-dhcp"
cipher AES-256-CBC
comp-lzo
auth SHA512
verb 4
proto tcp
dev-type tun
port 1194
dev tun0
#tun-mtu 1500
keepalive 10 30
client-config-dir ccd
I think this issue is not limited to WhatsApp alone, but any ESTABLISHED connections will have to wait 30 seconds to close and start a new one to get working.
How to fix this delay issue.?
Thanks in advance.
