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IPv6 Dropping; Losing Internet Connection

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brenkworth
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IPv6 Dropping; Losing Internet Connection

We are experiencing intermittent network drops on specific machines, not all at the same time.  When I checked the router I found these errors.     Could this be the cause ?   Can we just use IPv4 and turn off IPv6?

 

FW.IPv6 FORWARD drop, 2887 Attempts.2015/7/09 13:28:42Firewall Blocked
FW.IPv6 INPUT drop, 1472 Attempts.2015/7/09 13:28:42

Firewall Blocked

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Re: IPv6 Dropping; Losing Internet Connection

What model of modem are you using?  Are you running VoIP?

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Re: IPv6 Dropping; Losing Internet Connection

Hi - thanks for responding.  We are NOT running VOIP.  

 

Router info:

 

Model: DPC3939B
Vendor: Cisco
Hardware Revision: 1.0
Serial Number: 270416663
Processor Speed: 447.28 MHz
DRAM: 524288 MB
Flash: 128 MB


DOCSIS Software Version: dpc3939b-v303r204217-150321a-CMCST

Software Image Name: dpc3939b-v303r204217-150321a-CMCST.p7b
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Accepted Solution

Re: IPv6 Dropping; Losing Internet Connection

Call into Tech Support and ask they replace the modem with either an SMC D3G or a Netgear.

 

Use the SMC unless you have to make services on IPv6 available over the Internet - for example you are hosting a webserver that users on the Internet must attach to with IPv6.  In that case use the Netgear.  But the SMC is the best

modem for businesses who are just using it to get IPv4 and "IPv6 client" access to the Internet.  My last SMC D3G had an uptime of 4 years without a crash or dropped packet.

 

Neither of those 2 modems includes wifi so if you need wifi you will need to get a wifi access point (or use a wifi router as an access point)

 

The BWG that you have is known to have bugs with IPv6.  It is the newest of the CPEs in Comcast's lineup.  Basically what happens is when you sign up for a Comcast connection and you don't specify a modem you are given the BWG.  They do it because the BWG is an all-in-one and can do wireless and VoIP.  So if a customer calls into Comcast 2 months later and wants those services added to their account it saves the cost of a truck roll, they can just turn it on remotely.  it's not a bad modem, but in my opinion it's not appropriate for serious business use.  It's more appropriate for a residential setting or for a coffee shop..  Comcast does use it extensively for residential accounts.

 

As far as disabling IPv6, it can't be done on the BWG.  Of course, you can do it on devices plugged into the BWG.  But your going to break things you didn't expect to break.  Particulary with Windows 8 and above and the newer Microsoft server operating systems, IPv6 is used extensively now.  For example if you join a Windows system to a MS Domain, all your fileshareing networking takes place over IPv6 link-local connections.

 

If you really want to disable IPv6 and use the BWG then you have to install a router behind the BWG and call into Comcast and have them put the BWG into true bridged mode.  Then you can turn off IPv6 on your router.  But, that disables the wifi on the BWG and makes it impossible to use static IP addresses.  And of course your internal hosts are still going to run IPv6 when they talk amongst themselves.

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Re: IPv6 Dropping; Losing Internet Connection

Thank you.   I will request a new modem.  I appreciate it.

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4 REPLIES
Forum Contributor

Re: IPv6 Dropping; Losing Internet Connection

What model of modem are you using?  Are you running VoIP?

brenkworth
New Member

Re: IPv6 Dropping; Losing Internet Connection

Hi - thanks for responding.  We are NOT running VOIP.  

 

Router info:

 

Model: DPC3939B
Vendor: Cisco
Hardware Revision: 1.0
Serial Number: 270416663
Processor Speed: 447.28 MHz
DRAM: 524288 MB
Flash: 128 MB


DOCSIS Software Version: dpc3939b-v303r204217-150321a-CMCST

Software Image Name: dpc3939b-v303r204217-150321a-CMCST.p7b
Forum Contributor

Re: IPv6 Dropping; Losing Internet Connection

Call into Tech Support and ask they replace the modem with either an SMC D3G or a Netgear.

 

Use the SMC unless you have to make services on IPv6 available over the Internet - for example you are hosting a webserver that users on the Internet must attach to with IPv6.  In that case use the Netgear.  But the SMC is the best

modem for businesses who are just using it to get IPv4 and "IPv6 client" access to the Internet.  My last SMC D3G had an uptime of 4 years without a crash or dropped packet.

 

Neither of those 2 modems includes wifi so if you need wifi you will need to get a wifi access point (or use a wifi router as an access point)

 

The BWG that you have is known to have bugs with IPv6.  It is the newest of the CPEs in Comcast's lineup.  Basically what happens is when you sign up for a Comcast connection and you don't specify a modem you are given the BWG.  They do it because the BWG is an all-in-one and can do wireless and VoIP.  So if a customer calls into Comcast 2 months later and wants those services added to their account it saves the cost of a truck roll, they can just turn it on remotely.  it's not a bad modem, but in my opinion it's not appropriate for serious business use.  It's more appropriate for a residential setting or for a coffee shop..  Comcast does use it extensively for residential accounts.

 

As far as disabling IPv6, it can't be done on the BWG.  Of course, you can do it on devices plugged into the BWG.  But your going to break things you didn't expect to break.  Particulary with Windows 8 and above and the newer Microsoft server operating systems, IPv6 is used extensively now.  For example if you join a Windows system to a MS Domain, all your fileshareing networking takes place over IPv6 link-local connections.

 

If you really want to disable IPv6 and use the BWG then you have to install a router behind the BWG and call into Comcast and have them put the BWG into true bridged mode.  Then you can turn off IPv6 on your router.  But, that disables the wifi on the BWG and makes it impossible to use static IP addresses.  And of course your internal hosts are still going to run IPv6 when they talk amongst themselves.

brenkworth
New Member

Re: IPv6 Dropping; Losing Internet Connection

Thank you.   I will request a new modem.  I appreciate it.

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