New Poster
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2 Messages
inbound port blocking
I use a Meraki MX64 firewall, which supports a L2TP based VPN. Previously I have been able to VPN back to this equipment while on the road, so I know that my firewall and client setups are correct. However since switching to Comcast I can no longer do so. Connection from the outside simply time out and according to the VPN logs on my firewall a connection never makes to the device to even log. I can ping the firewall, so basic connectivity is there.
So, is Comcast blocking inbound ports, specifically ports 500 and 4500 for UDP traffic? If yes, who can I reach to release these ports to the house?
Thanks,
peter
BruceW
Gold Problem Solver
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26.5K Messages
6 years ago
What modem, eMTA, or gateway are you using? Comcast blocks the ports listed on https://www.xfinity.com/support/articles/list-of-blocked-ports for all of these, but the gateways include their own firewall which may be set to block other ports as well.
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peter_bako
New Poster
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2 Messages
6 years ago
I have a CGM4140COM according to the My Account page. When my account was initially setup, I had support put it into bridge mode, so my own firewall and networking equipment can get the external IP and do all of the protection. This the same thing I have done with my last two ISPs.
However based on your comment, I realised that the Xfinity modem is accessible from my network and even in bridge mode has its firewall enabled (though set to Low security mode) - this is different from the last two ISPs and their modems. I then disabled the firewall function on the Xfinity modem hoping that it would solve the issue. Today I had a chance to jump on an external network again and tried to connect, but am having the same issue. I can ping my home firewall, but the VPN connection never goes through, and the logs of it do not even show an incoming attempted connection. Something is still blocking things.
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EG
Expert
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111.4K Messages
6 years ago
If the gateway is truly in full bridge mode, all NAT / routing / firewall / WiFi functions should be disabled. Double-check that it truly is in full bridge mode.
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Jlavaseur
Problem Solver
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948 Messages
6 years ago
I have that same gateway, from the admin panel you can setup ports you want forwarded, try forwarding the ports that you need to use and see if that helps
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ITGUY05
New Poster
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1 Message
5 years ago
Was there any resolution here? I am experiencing the same issue with myself and another remote user, both of us Comcast users.
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EG
Expert
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111.4K Messages
5 years ago
.@ITGUY05
Please create you own new topic here on this board detailing your issue, thanks. Dead thread from last year now being closed.
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