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No internet connectivity on client

Posted: Fri Jan 28, 2022 12:32 pm
by Amareshwari
Hi,

We were running OpenVPN without any issues for past 1 year. And clients started to see connection time out issue from last day. After enabling logs on server we saw the following error :

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VERIFY ERROR: depth=0, error=CRL has expired
So, we regenerated CRL with

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./easyrsa gen-crl
and updated server and restarted. After which client started to connect fine, but internet connectivity is not available on client . All clients are facing the same issue. Can somebody guide us where is it going wrong?

Here are the server configuration for redirecting client traffic :

push "redirect-gateway def1 bypass-dhcp"
push "dhcp-option DNS 208.67.222.222"
push "dhcp-option DNS 208.67.220.220"

Same configuration was working all well till last 2 days. Really appreciate any help on fixing this further.

Thanks
Amareshwari

Re: No internet connectivity on client

Posted: Fri Jan 28, 2022 4:50 pm
by TinCanTech

Re: No internet connectivity on client

Posted: Sat Jan 29, 2022 1:20 am
by openvpn_inc

Re: No internet connectivity on client

Posted: Sat Jan 29, 2022 5:23 am
by Amareshwari
Thanks for the flow chart shared. It is failing at pinging 8.8.8.8. And IP forwarding and NAT is enabled, but still pinging 8.8.8.8 is problem.
Below are the configuration. Can you let us know if anything more need to be done ?

And as per the flowchart, client and server are not on the same LAN, and chart says likely firewall issue? What sort of firewall issue would cause this. There are no firewall issue on the vpn server itself for internet traffic. Please let us know what can be done further.

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$ sudo sysctl -p
net.ipv4.ip_forward = 1

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$ ip route | grep default
default via 10.160.0.1 dev eth0 

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$ cat /etc/ufw/before.rules
#
# rules.before
#
# Rules that should be run before the ufw command line added rules. Custom
# rules should be added to one of these chains:
#   ufw-before-input
#   ufw-before-output
#   ufw-before-forward
#

# START OPENVPN RULES
# NAT table rules
*nat
:POSTROUTING ACCEPT [0:0]
# Allow traffic from OpenVPN client to eth0 (change to the interface you discovered!)
-A POSTROUTING -s 10.8.0.0/8 -o eth0 -j MASQUERADE
COMMIT
# END OPENVPN RULES

# Don't delete these required lines, otherwise there will be errors
*filter
. . .

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$ cat /etc/default/ufw
DEFAULT_FORWARD_POLICY="ACCEPT"

Re: No internet connectivity on client

Posted: Mon Jan 31, 2022 7:03 am
by Amareshwari
Hi,

Can somebody help what can be done to avoid this problem?

Thanks

Re: No internet connectivity on client

Posted: Mon Jan 31, 2022 4:08 pm
by TinCanTech
Sanitised output of

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ip a