Re: rpc.nfsd Host Option & IPv6

[Kinglong Mee <kinglongmee@gmail.com>]

On 6/7/2015 5:06 PM, Kinglong Mee wrote:
> Cc steve,
> 
> On 6/3/2015 9:39 PM, Sean Elble wrote:
>> Hi all,
>>
>> While it seems that most folks use iptables to restrict access to single interfaces when multihomed hosts are acting as NFS servers, I do see that there is a "--host" option that can be provided to rpc.nfsd when it starts so that it only binds to a specific IP/interface.
>>
>> This does seem to work nicely, but when I try to use it, it throws an error/warning (where nfs-server is defined in /etc/hosts for the IPv4 address of the interface I wish for TCP port 2049 to be opened on):
>>
>> rpc.nfsd: unable to resolve nfs-server:nfs to inet6 address: Name or service not known
> 
> It is caused by that rpc.nfsd try to bind IPv4 and IPv6 address default.
> you don't support an IPv6 address, so rpc.nfsd print the message.
> 
> But, IPv4 is work correctly.
> 
>>
>> Commenting out the following lines in /etc/netconfig (as suggested by the Google) allows the daemon to start without error:
>>
>> udp6       tpi_clts      v     inet6    udp     -       -
>> tcp6       tpi_cots_ord  v     inet6    tcp     -       -
> 
> If you comment those lines, rpc.nfsd will check /etc/netconfig and find udp6/tcp6 is not allowed,

Sorry, udp6/tcp6 should be inet6 here.

thanks,
Kinglong Mee

> so, rpc.nfsd will not bind IPv6 address, the message is not printed.
> 
>>
>> But I'm wondering if that is the only means for this to work, particularly considering that I'd expect changes to /etc/netconfig to apply to more than just rpc.nfsd.
> 
> Agree with you.
> 
>>
>> It is worth noting that 1) this seems to apply equally to Debian-based and RHEL-based systems and 2) things seem to work even with the error, but I wouldn't have expected to see that message for something (seemingly) so simple.
> 
> I think we should not print the message as you want.
> 
> thanks,
> Kinglong Mee
>