Skip to content
U

New Contributor

 • 

2 Messages

Thu, Sep 23, 2021 4:41 PM

Cannot get IPv4 connectivity but IPv6 works

New installation and have had a static IP assigned and have tech support configure the modem in the pass-thru mode.  Have tried configuring with my firewall but was unable to get connectivity but assigning the Public IP to a network port on a laptop was able to get online but only to IPv6 sites.  

Even checking on whatismyipaddress.com.  

IPv6: ? 2603:3014:2b03:2400:f44e:df01:2fb3:4ee7
IPv4: ? Not detected

Official Employee

 • 

23 Messages

1 m ago

Hello @user_8b55e3! If you cannot connect to the server that is statically configured behind the IP Gateway, it may be because of these two reasons.

  • Is the firewall disabled on the Gateway?
  • Is smart packet detection enabled?

New Contributor

 • 

2 Messages

1 m ago

I think so but I cannot find any section for smart packet detection.

This is a cga4131com rev 2.3 comcast router.

Bridge Mode Disabled

DHCP is disabled

Firewall
 IPv4
check Disable Firewall for True Static IP Subnet Only
unchecked Disable Ping on WAN interface
 Custom Security

LAN-to-WAN : Allow all.

WAN-to-LAN : IDS Enabled and block as per selections below.

unchecked Block http (TCP port 80, 443)
unchecked Block ICMP
unchecked Block Multicast
unchecked Block Peer-to-peer applications
unchecked Block IDENT (port 113)
checked Disable entire firewall


 IPv6
unchecked Disable Ping on WAN interface
Custom


LAN-to-WAN : Allow all.

WAN-to-LAN : IDS Enabled and block as per selections below.

unchecked Block http (TCP port 80, 443)
unchecked Block ICMP
unchecked Block Multicast
unchecked Block Peer-to-peer applications
unchecked Block IDENT (port 113)
checked Disable entire firewall

On my devices that I've used for testing I set the static IP and Gateway info in my IPv4 settings but the only IPv4 address I can reach is the comcast router on 10.1.10.1

ip 96.x.x.121

sub 255.255.255.252

gtw 96.x.x.122

New Contributor

 • 

7 Messages

@user_8b55e3 I should add that we have our own firewall configured for IPv4 to keep compatibility for VPN connections.  For testing I've tried various computers Windows and MacOS connected directly to the router with the static IP assigned to them.

Official Employee

 • 

13 Messages

That may be why. Could you disable your personal firewire momentarily and try again?

New Contributor

 • 

7 Messages

No luck, pinging a site just returns the IPv6 address and if i try "ping -4 comcast.net" it times out.  I am using a laptop plugged directly into the Comcast Router and have the public IP address assigned to the network port on the laptop.  To be thorough I disabled Windows Firewall and tried that way too.

Official Employee

 • 

44 Messages

@user_ac99f8 Have you checked out this link yet to cover all possible issues:  https://comca.st/39CMf4K.

New Contributor

 • 

7 Messages

Yes, I went through that link several times this week.

New Contributor

 • 

7 Messages

17 d ago

This was resolved by Tier 2 support.  Our static IPv4 address had been assigned to another modem.