jail and networking

[Devin Teske]

> -----Original Message-----
> From: owner-freebsd-questions at freebsd.org [mailto:owner-freebsd-
> questions at freebsd.org] On Behalf Of doug at safeport.com
> Sent: Thursday, February 21, 2013 11:00 AM
> To: Shane Ambler
> Cc: freebsd-questions at freebsd.org; Bernt Hansson
> Subject: Re: jail and networking
> 
> On Thu, 21 Feb 2013, Shane Ambler wrote:
> 
> > It's been a while since I experimented with jails but I'm pretty sure it is
> > the reason I changed my sshd_config
> >
> > When you start sshd on the base system by default it binds against 0.0.0.0
> > and :: which is every ip4 and ip6 address configured on the base system,
> > which includes the aliased ip's for your jails. This is represented by the
> > *:22 from sockstat. When you start the jail it can't start sshd because the
> > base already has that address/port in use.
> >
> > In /etc/ssh/sshd_config comment out the ListenAddress 0.0.0.0 and
> > ListenAddress :: then add ListenAddress 10.0.0.3
> >
> > service sshd restart
> >
> > start your jail and try again
> >
> > The jail config is fine as the jail only sees the one ip address assigned to
> > it.
> 
> This is what fixed the problem. From the jail man page, "... The following
> frequently deployed services must have their individual configuration files
> modified to limit the application to listening to a specific IP address ...".
It
> then specifically mentions ssh and send mail.
> 
> The system I looked at runs seven jails fine without my having made that
change.
> I am not sure why I am getting away with this, but I also thank you
> 

What I find strange is that:

1. I knew about ListenAddress w/respect to jails, but...

2. We are not changing it (sshd_config has no ListenAddress -- leading to
default values used), yet...

3. Base machine and jails both work fine

Not sure when it's required versus not, because we're running fine without that
change here with over a dozen jails.

The only thing I've ever noticed is that we tend to use
jail_NAME_ip="iface|addr" while most everybody else seems to be using
jail_NAME_ip="addr".
-- 
Devin

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