Lightspoke Documentation Resource
Business Web Application Platform
Web-Based Database
Sendmail + UUCP HOWTO
Author:
Jamal Hadi Salim ([email protected] or [email protected])
History:
Initial edition July/96: works only with non-bind edition of sendmail
Oct 01 /96: works with the redhat supplied binary
Oct 07 /96: added/modified a tip on how to compile non-bind sendmail
Oct 25 /96: added/modified a tip on how to keep sendmail getHostbyAddr() happy via a dummy /etc/hosts entry
Mar 15 /97: I am amazed at the response/feedback i am receiving so i decided to refine this further. Fixed some small errors; added diagram + references.
Oct 25/97: Htmlise+ add blurb on DNS capable machines
After finally settling down and properly reading TFM (the Bat Book, to be precise) i have solved the Caramilk secret! The steps below have been tested with the binary supplied by RedHat. Perhaps i should send this tip to the maintainer of the Sendmail FAQ too since there is absolutely no mention of UUCP interworking with sendmail there.
What this Document tries to show you
How to setup a single machine, reffered to as
me.com
in the example, with no direct access to the internet to route mail for you via sendmail and UUCP to a 'smarter host' eg your ISP.
Optionally you can configure this machine to feed other machines i.e you are their 'smart' host or gateway.
What this Document does not tell you
I have been receiving incredible number of questions regarding topics which are beyond the focus of this HOWTO. The purpose of this document is not to describe them so please try not send me any questions on the following:
a) How to setup UUCP.
Refer to many fine references on this, including:
UUCP HOWTO (Vince Skahan, )
Using and managing UUCP (Ed Ravin et al -- publisher O'reilly) which i think is the best authority on UUCP
Linux Network Administrator Guide (Olaf Kirch)
b) how to setup DNS.
Refer to the many fine references on this, including:
Caching named mini howto (Nicolai Langfeldt)
The bat book (Sendmail;Costalles, Allman, Rickert;publisher O'reilly)
DNS and BIND (Publisher O'reilly)
TCP/IP Network Administration (Hunt, Craig;Publisher O'reilly)
Linux Network Administrator Guide (Olaf Kirch)
sendmail Theory and Practice (Avolio and Vixie; publisher Digital press)
c) how to setup databases (other than the mailertable) to work with sendmail.
Refer to the many fine references on this, including:
The bat book (Sendmail;Costalles, Allman, Rickert -- publisher O'reilly)
TCP/IP administration (Publisher O'reilly)
Sendmail Theory and Practice (Avolio and Vixie; publisher Digital press)
Docs bundled with sendmail d) how to write or modify rulesets or mailers.
All the above references in c)
You can also find help on the following
newsgroups
:
comp.mail.sendmail
comp.mail.uucp
comp.os.linux.networking
IRC channels
#linux, #unix
THE SETUP
This is for a system, hypothecally named
me.com
, whose mail is sent out only via UUCP.
mysmarthost
is the ISPs hostname as set up in the
uucp sys file
and
me.com
is the hostname we use or are known by in the MX records on the internet.
mysmarthost
hooks to the internet. We really dont care how it does it, we just know it knows how to get us there.
me.com
, whose setup we describe in the example, feeds sites
down.com
and
system1.org
and their subnodes.
me.com
connects to
down.com
via TCP/IP and connects to
system1.org
via raw UUCP using a phone line.
The setup description is shown below:
------------------------ | | | Internet | | | ----------------------- | | PPP/dedicated line running TCP-IP | ------------- | | |mysmarthost | Authoritative name server for | | *.me.com, *.down.com, *.system1.org | | -------------- | | UUCP via a phone line receive for | system1.org, *.system1.org,*.down.com, down.com | as well as me.com and *.me.com ------------ | * ***** * | ------------ | * me.com * | ------ | * * | | | | * ***** * | | | ------------ | |UUCP via phone line | uucp via TCP/IP | | ----------- ----------- | | | | |system1.org| | down.com |------- | | | | | ---------- ------------ | | | | | | | LAN: smtp to nodes | UUCP phone line | | ----------- ------------- | | | | |system1's| | down's | |subnodes | | LAN | | | ------------ ----------
pre-requisites
1)
If you are already running DNS or have a pointer to a DNS server (in your /etc/resolv.conf) and are on a live connection to the net then skip this part. You are safe. You dont have to do any 'smart' thing skip to
2)
If you are on a machine using uucp for mail then you dont really need to compile bind/resolv into sendmail;
How to survive name canonicalization on a stand-alone machine with no DNS
PART I
If you get a pre-compiled sendmail with BIND in it you can still live with it (As is the case with Redhat supplied sendmail).
a) Refer to my solution for this based on the m4 file described (my favorite). Try to use this option unless you really insist on b) or c) below OR
b)If you talk to me i could supply you with a non-BIND compiled version (8.8.5). Perhaps RedHat should consider supplying two sendmail binaries (like slakware) One with BIND and the other with no BIND. OR
c) The quickest solution to get sendmail with no bind is to edit
src/conf.h
lines below to read as i have shown:
# ifndef NAMED_BIND conf.h:# define NAMED_BIND 0 /* use Berkeley Internet Domain Server */
PART II
:
Sendmail would however normally insist on doing name look ups to resolve the host part using
gethostbyaddr()
for each email it sends (even if you tell it not to canonify names).
a) use an
RFC1597
IP address (10.0.0.0-10.255.255.255, 172.16.0.0-172.31.255.255, 192.168.0.0-192.168.255.255)
Edit
/etc/hosts
and add the following as a sample for the host myhost
10.0.0.1 myhost.me.com myhost
or
b) If you use NIS (and NIS is compiled into sendmail as seems to be the case in Redhat. ) make sure the
/etc/nsswitch.conf
file contains:
hosts: files dns
and in
/etc/hosts
and add the following as a sample for the host myhost [again using RFC1597 IP addressing scheme]
10.0.0.1 myhost.me.com myhost
NOTE:
---- In both a) and b) above it is critical that you list the long (fully qualified) in the /etc/hosts file used. i.e the line should read
10.0.0.1 myhost.me.com myhost
and NOT
10.0.0.1 myhost
you will also need to define the sendmail
$w
macro to hold
myhost.me.com
add the Following line to your
/etc/sendmail.cf
after it is generated
Djmyhost.me.com
(or you can use
MASQUAREADE_AS(myhost.me.com)
in the
.mc
below)
NOTE
!!!!!
myhost
as a domain name is given as an example; you dont have to use it as is. Pick your own hostname if you dont have one already.
2)
Ensure that you have makemap and it is capable of supporting hash and or the more common dbm format or even btree format (The Redhat version does not support dbm). Makemap is normaly distributed with sendmail.
SETUP (the mc file)
I) create your .mc file using your favorite editor; i'll call this file
my.mc
a) No DNS -- standalone
i
nclude(`../m4/cf.m4')
VERSIONID(`me.com's setup with uucp created by xxxx --no dns ')
dnl OSTYPE(linux)
FEATURE(nodns)dnl
FEATURE(nocanonify)dnl
FEATURE(always_add_domain)dnl
FEATURE(mailertable, hash /etc/mailertable)dnl
MAILER(local)dnl
MAILER(smtp)dnl
MAILER(uucp)
define(`SMART_HOST', uucp-dom:mysmarthost)
Let's dissect this:
include(`../m4/cf.m4')
requests for the m4 macro found in ../m4/cf.m4 to be include to resolve some things
VERSIONID(`me.com's setup with uucp created by xxxx')dnl
This is used to distinguish the different versions of .cf file you might end up creating.
OSTYPE(linux)
This is used to define/redefine linux specific stuff. It is safe to have it here.
FEATURE(nodns)dnl
This says we dont have a DNS server (so in effect we are using uucp only for mail. Sendmail must be compiled not to use bind) This is now obsolete. I will let it stay here just in case you use an older version of sendmail.
FEATURE(nocanonify)dnl
This says Don't pass addresses to
$[ ... $]
for canonification. Normally if you have BIND compiled in sendmail would try and expand the alias/IP address to a canonical name using DNS. You dont wanna do this if all you have are feeds which connect to you via UUCP i.e you are a stand alone.
FEATURE(always_add_domain)dnl
This adds the local domain host name even on locally delivered mail Not necessary i just like it;
This might not be a safe feature since spammers, with proper setup conditions, can abuse you
.
me.com is not connected to the net via tcp/ip so it is safe
FEATURE(mailertable, hash /etc/mailertable)dnl
the file
/etc/mailertable
is going to be a
hash
database where we will store routing information of certain sites. If you dont have anyone who you feed uucp to then you dont need this. More on this later. If you wanted to use the
dbm
format you would have
FEATURE(mailertable, dbm /etc/mailertable)dnl
If you wanted to use the
btree
format you would have
FEATURE(mailertable, btree /etc/mailertable)dnl
MAILER(local)dnl MAILER(smtp)dnl MAILER(uucp)
These are the mailers we use.
define(`SMART_HOST', uucp-dom:mysmarthost)
Our smart host is our ISP who is defined in the uucp
sys
file as
system mysmarthost
. Any messages that we cant handle (i.e ones for domains or mailers we dont understand) will be passed on to our smarthost/ISP to figure out. note we use uucp-dom as the uucp mailer. This particular mailer uses smtp rewriting rules.
b) DNS on
include(`../m4/cf.m4')
VERSIONID(`me.com's setup with uucp created by xxxx --dns enabled')dnl
OSTYPE(linux)
FEATURE(always_add_domain)dnl
FEATURE(mailertable, hash /etc/mailertable)dnl
MAILER(local)dnl
MAILER(smtp)dnl
MAILER(uucp)
define(`SMART_HOST', uucp-dom:mysmarthost)
II) create your sendmail.cf file
a) backup your old
/etc/sendmail.cf
file
b) overwrite the sendmail.cf with the new one:
m4 my.mc > /etc/sendmail.cf
c) verify that the sendmail.cf file was correctly created based on your specifications.
Some of the gotchas that i came across were: -
missing uucp-dom mailer
This was because i didnt have the smtp mailer entry. Actually, i understand it is important to have it defined before the uucp
III) create your /etc/mailertable
if you dont have uucp sites feeding off you skip this step
a) create/edit the file /etc/mailertable
sample /etc/mailertable
system1.org uucp-dom:system1
.system1.org uucp-dom:system1
down.com uucp-dom:down
up.down.com error: Host is unknown at me.com
.down.com uucp-dom:down
.me.com error: Host unknown at me.com
This says anything that is addressed to
system1.org
or to
*.system1.org
that we receive will be sent using the
uucp-dom
mailer and be delivered to
system1
(defined in the the uucp
sys
file) in other words we are doing the mail routing for
*.system1.org ;
similar for
down.com
and its subnodes except for the additional filtering; we bounce back any mail for down's subnode
up.down.com
using sendmail's built-in
error
mailer with the message
"Host is unknown at me.com"
; This is because we have been asked to do this by the admin at
down.com.
To bounce unknown subdomains to us we use the last line in the mailertable (which is what all unknown nodes default to).
b) create the database with
makemap
if you use
hash
:
makemap hash /etc/mailertable < /etc/mailertable
if you use
dbm:
makemap dbm /etc/mailertable </etc/mailertable
if you use
btree:
makemap btree /etc/mailertable </etc/mailertable
do this every time you change the file.
IV) restart sendmail
V) test sendmail
i) sendmail -bv user@destination
ii) using sendmail -bt and enter various addresses using 3,0
ruleset to see where they end up and the various rulesets and cf walks taken.
You are set!
TODO
1) Add info on setting up system down.com (so as to show how to
take care of those smtp nodes)
2) Add info on how to setup news to be delivered via UUCP
(preferably INN). This might require changing the title of the doc.
This resource is mirrored from the Linux Documentation Project. It was posted as a resource for all. Courtesy of Lightspoke: The web-based database company.
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