Author Topic: Firewall appears to be blocking some incoming OpenVPN requests  (Read 285 times)

Offline DLW

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I have an OpenVPN server running on my router.  I connect through a PC at the remote end and can ping a PC on my local network over the OpenVPN link.  If I try to browse shares on the same PC with the firewall active I get a network path not found but if I disable the firewall I can browse the shares as I would expect.  However, with the firewall enabled there is nothing being recorded as an intrusion.  Wireshark sees the incoming packets, which look identical in both cases.  If I am reading them correctly the first packet is a SYN request which is not getting answered.

Offline jljtgr

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Re: Firewall appears to be blocking some incoming OpenVPN requests
« Reply #1 on: June 10, 2019, 03:10:14 PM »
My guess is that you're using a TUN interface which means that VPN clients will not take IPs from your LAN DHCP pool.  Comodo by default will block most incoming packets for network zones that you do not have a network interface for...  IE, the Internet.  Because your computer does not have a network interface for your VPN's network, it will not have offered to create an allowed network zone.

You'll have to go into the Firewall -> Global Rules and either add an allow rule for the router's OpenVPN range or remove the Block-all rule at the bottom.

Offline DLW

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Re: Firewall appears to be blocking some incoming OpenVPN requests
« Reply #2 on: June 10, 2019, 10:48:55 PM »
Sorry, should have said that I've already added the IP range for the OpenVPN to the Zone.

Offline jljtgr

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Re: Firewall appears to be blocking some incoming OpenVPN requests
« Reply #3 on: June 11, 2019, 12:22:06 AM »
I feel like I have a very similar setup and I don't encounter this issue.  It really sounds like your Global Rules are not configured properly, as the default Block-all rule won't log events.  You can try deleting the block-all rule as a test. 

Aside from revising your Global Rules section, my only suggestion is to look at the "System" entry in Application Rules.  Though, I don't think there's a block rule on that by default, so it wouldn't cause a silent block.

Offline DLW

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Re: Firewall appears to be blocking some incoming OpenVPN requests
« Reply #4 on: June 11, 2019, 05:39:51 PM »
I'm beginning to think that there is a much bigger problem. I'm on Windows 10 Insider Build 18912 and I only just noticed that the firewall is sitting there showing no connections, which must be impossible.  If it wasn't for the fact that pings are getting through and I am not having any problems using the machine I might think that the firewall was in block mode.  Are there any settings in Comodo which would allow me to see the actual traffic it is handling and what it is doing with it.

Offline DLW

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Re: Firewall appears to be blocking some incoming OpenVPN requests
« Reply #5 on: June 20, 2019, 11:58:37 AM »
The issue with the No Connections was cured by reinstalling CIS.  I've not had an opportunity to find out if this has affected the OpenVPN issue

 

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