Re: [courier-users] What to restart when DNS changes?

[Lyndon T. <lt...@al...>]

On Wed, 15 Mar 2006 18:12:44 -0500 mr...@co... wrote:
> Lloyd Zusman writes:
> 
> > One of the domains that I host is for a user whose machine gets a
> > dynamic IP address.  Therefore, the "A" record in the DNS entry for that
> > domain changes from time to time.
> > 
> > I handle this user's email with my Courier server, and I'm wondering if
> > I need to do a "courier restart" every time his DNS changes.  The "MX"
> > record (which, of course, points to my Courier server) remains the same,
> > but will the change of his "A" record require me to restart Courier, for
> > any reason?
> 
> Courier does not cache DNS data itself.  A DNS request is made for each 
> message to a new domain.  You only need to deal with caching in your DNS 
> server.
> 

Let me correct myself, DNS caching was our first theory, on further research, what probably happened is that authdaemond opens up a few "pooled" tcp connections to the ldap server. Then keeps these open. We removed the LDAP DNS record after the pooled connections had been established. The authdaemond kept the pooled connections for a while so things did not break right away. The pooled connections must have been recycled or the courier process restarted. Authdaemond then tried to re-connect to the LDAP server but since the DNS record has disappeared, authdaemond complained and authentication broke.

--
Lyndon Tiu