# FreeBSD intermittent with ipv6 @ VPS



## cybersans (Jan 19, 2019)

Dear FreeBSD forumers.

I am a new guy here. The reason why I post this topic just to get an idea since my VPS provider cannot solve this problem.

I bought a VPS, actually 2, one is several years ago and one just a week ago. They share the same problem and another similarities is located at same place which is London but based on IP whois they are using different DC.

The problem is when I installing FreeBSD no matter what version, the IPv6 will become intermittent, means it will be timeout after several ping to outside ipv6. After several timeouts it resume replying with a lag, almost 2 seconds. After several reply with a constant 1-2ms, it lost again.

They provide me with /64 IPv6 while the gateway IP were in 48 prefix, so in the rc.conf I put prefixlen 48 in every IPv6 list.

This problem is not happening if I installing and using Linux templates provided by them.

Are there possible some routers/gateways/firewall filtering unrecognized traffic from unrecognized operating system?


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## PstreeM (Feb 11, 2021)

Hello: 

Also met this problem.

The ipv4 is working well.
but for the ipv6, ping external lossed packet more than 50%.

Connection from external to the server, normally is timeout.
but if I use the traceroute6 to any ipv6 address in the system. I can reach this server quickly.

It’s something I missed ?


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## SirDice (Feb 11, 2021)

cybersans said:


> They provide me with /64 IPv6 while the gateway IP were in 48 prefix, so in the rc.conf I put prefixlen 48 in every IPv6 list.


This is likely your problem. Set the prefix to /64. You might need to fiddle a bit with static routes because the gateway is outside of your subnet. Linux and Windows seem to accept this, FreeBSD does not. 



cybersans said:


> Are there possible some routers/gateways/firewall filtering unrecognized traffic from unrecognized operating system?


OS is irrelevant for TCP/IP, both on IPv4 and on IPv6.


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