Resolving localdomain

Hi,

I have an Exim setup where I wish to forward all mail to
myuser@localdomain, this is done by adding a route and mapping all
users to myuser@localdomain

Exim tries to resolve the domain using DNS, but fails:

calling dnslookup router
dnslookup router called for myuser@localdomain
domain = localdomain
DNS lookup of localdomain (MX) gave HOST_NOT_FOUND
returning DNS_NOMATCH
dnslookup router declined for tagticks@localdomain
"more" is false: skipping remaining routers
no more routers

Any way I can trick my machine into resolving localdomain to 127.0.0.1?

Thanks.

Morten

On 27 Dec 2006 13:20:09 -0800, Morten
<(E-Mail Removed)> wrote:
>
>
>
> Hi,
>
> I have an Exim setup where I wish to forward all mail to
> myuser@localdomain, this is done by adding a route and mapping all
> users to myuser@localdomain
>
> Exim tries to resolve the domain using DNS, but fails:
>
> calling dnslookup router
> dnslookup router called for myuser@localdomain
> domain = localdomain
> DNS lookup of localdomain (MX) gave HOST_NOT_FOUND
> returning DNS_NOMATCH
> dnslookup router declined for tagticks@localdomain
> "more" is false: skipping remaining routers
> no more routers
>
> Any way I can trick my machine into resolving localdomain to 127.0.0.1?
>
Is localdomain in /etc/hosts?

> Thanks.
>
> Morten
>


--
Now I think I just reached the state of HYPERTENSION that comes JUST
BEFORE you see the TOTAL at the SAFEWAY CHECKOUT COUNTER!

"Morten" <(E-Mail Removed)> wrote:
>Hi,
>
>I have an Exim setup where I wish to forward all mail to
>myuser@localdomain, this is done by adding a route and mapping all
>users to myuser@localdomain
>
>Exim tries to resolve the domain using DNS, but fails:
>
>calling dnslookup router
>dnslookup router called for myuser@localdomain
> domain = localdomain
>DNS lookup of localdomain (MX) gave HOST_NOT_FOUND
>returning DNS_NOMATCH
>dnslookup router declined for tagticks@localdomain
>"more" is false: skipping remaining routers
>no more routers
>
>Any way I can trick my machine into resolving localdomain to 127.0.0.1?

You *do* *not* want it to resolve to 127.0.0.1, which should resolve
only to "localhost".

The right way to get a local loopback is to use another IP address. If
you take a look, you'll find that *any* 127.x.x.x address is going to
be a local loopback, hence any IP address in that range will do what
you need.

Put something like this in /etc/hosts,

127.0.0.2 localdomain

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) (E-Mail Removed)

(E-Mail Removed) (Floyd L. Davidson) writes:

> If
>you take a look, you'll find that *any* 127.x.x.x address is going to
>be a local loopback, hence any IP address in that range will do what
>you need.

Sorry that I have to correct you in 2007:

The (x)Ntp-Daemon uses (did use with SusSe-8.0 anyway) some of the
adresses 127.127.x.y for connecting to local hardware-clocks.

In my system, I use(d) a line like this:

<---------

################################################## ##############################
## /etc/ntp.conf
##
## Sample NTP configuration file.
## See package 'xntp-doc' for documentation, Mini-HOWTO and FAQ.
## Copyright (c) 1998 S.u.S.E. GmbH Fuerth, Germany.
##
## Author: Michael Andres, <(E-Mail Removed)>
##
################################################## ##############################

##
## Radio and modem clocks by convention have addresses in the
## form 127.127.t.u, where t is the clock type and u is a unit
## number in the range 0-3.
##
## Most of these clocks require support in the form of a
## serial port or special bus peripheral. The particular
## device is normally specified by adding a soft link
## /dev/device-u to the particular hardware device involved,
## where u correspond to the unit number above.
##
## Generic DCF77 clock on serial port (Conrad DCF77)
## Address: 127.127.8.u
## Serial Port: /dev/refclock-u
##
## (create soft link /dev/refclock-0 to the particular ttyS?)
##
#
server 127.127.8.0 mode 5 prefer

<----------

Happy new year, Holger

Holger Petersen <(E-Mail Removed)> wrote:
>(E-Mail Removed) (Floyd L. Davidson) writes:
>
>> If
>>you take a look, you'll find that *any* 127.x.x.x address is going to
>>be a local loopback, hence any IP address in that range will do what
>>you need.
>
>Sorry that I have to correct you in 2007:
>
>The (x)Ntp-Daemon uses (did use with SusSe-8.0 anyway) some of the
>adresses 127.127.x.y for connecting to local hardware-clocks.

Nope, it doesn't do that! What it does is use a pseudo-IP
address to _select_ which driver it will use, but it does *not*
connect to the driver using that IP address.

The reason for using 127.127.x.x is because it is in fact a
local loopback, and will connect to the "lo" device.

The trick is that the lo device is configured with a mask of
255.0.0.0, so only the first number in a "dotted quad" will
actually make any difference.

You can verify that on an idle system fairly easily by pinging
any specific 127.x.x.x address while checking output from
"config lo" from before and after. You'll see the various
counters change, indicating that traffic was sent/received by
the lo device.

Just be aware that if you ping *any* IP address assigned to an
interface on the same host the data will go to the lo device,
not to the configured device. Hence if you have an ethernet
interface eth0 that is assigned an IP address like 192.168.1.5
you can ping that address and get counts on the lo device
(assigned to 127.0.0.0 or 127.0.0.1) instead of to the eth0
device.

That is a bit of "magic" internal to the TCP/IP stack.

>In my system, I use(d) a line like this:
>
><---------
>
>################################################# ###############################
>## /etc/ntp.conf
>##
>## Sample NTP configuration file.
>## See package 'xntp-doc' for documentation, Mini-HOWTO and FAQ.
>## Copyright (c) 1998 S.u.S.E. GmbH Fuerth, Germany.
>##
>## Author: Michael Andres, <(E-Mail Removed)>
>##
>################################################# ###############################
>
>##
>## Radio and modem clocks by convention have addresses in the
>## form 127.127.t.u, where t is the clock type and u is a unit
>## number in the range 0-3.
>##
>## Most of these clocks require support in the form of a
>## serial port or special bus peripheral. The particular
>## device is normally specified by adding a soft link
>## /dev/device-u to the particular hardware device involved,
>## where u correspond to the unit number above.
>##
>## Generic DCF77 clock on serial port (Conrad DCF77)
>## Address: 127.127.8.u
>## Serial Port: /dev/refclock-u
>##
>## (create soft link /dev/refclock-0 to the particular ttyS?)
>##
>#
>server 127.127.8.0 mode 5 prefer
>
><----------
>
>Happy new year, Holger

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) (E-Mail Removed)