msir@sulu.cc.rochester.edu (Mark Sirota) (09/20/90)
I realize that this is discussed all the time, but I've never paid attention
before because it was never an issue for me... But now I want to start
remote-mounting /usr/spool/mail for a cluster of diskless Sun workstations
currently running SunOS 4.0.3.
Currently I use my own sendmail.cf, which is exactly the same for all
machines on our network. It does all delivery itself, rather than
forwarding on to a central mailhost. Now, for this new setup, I'm going to
want all local delivery to be done by the server, so that multiple machines
don't all go writing into the same file at the same time, right?
I'm told I need to use the 'R' option for this. The manual is pretty
useless on this, it says "Remote mode. Deliver through remote SMTP server.
Default is location of /var/spool/mail."
What does this *really* do? (I don't have sources.) Can I just add this
option with the name of the fileserver, or do I need to completely rework my
sendmail.cf to forward all local mail on to the server?
Thanks muchly in advance.
--
Mark Sirota - University of Rochester Computing Center, Rochester NY
Internet: msir@cc.rochester.edu
Bitnet: msir@uordbv.bitnet
UUCP: {decvax,harvard,ames,rutgers}!rochester!ur-cc!msirmoore@betelgeuse.cs.utk.edu (Keith Moore) (09/21/90)
In article <9566@ur-cc.UUCP> Mark Sirota <msir@cc.rochester.edu> writes: >I realize that this is discussed all the time, but I've never paid attention >before because it was never an issue for me... But now I want to start >remote-mounting /usr/spool/mail for a cluster of diskless Sun workstations >currently running SunOS 4.0.3. Good idea. >Currently I use my own sendmail.cf, which is exactly the same for all >machines on our network. It does all delivery itself, rather than >forwarding on to a central mailhost. Now, for this new setup, I'm going to >want all local delivery to be done by the server, so that multiple machines >don't all go writing into the same file at the same time, right? Right. >I'm told I need to use the 'R' option for this. The manual is pretty >useless on this, it says "Remote mode. Deliver through remote SMTP server. >Default is location of /var/spool/mail." > >What does this *really* do? (I don't have sources.) Can I just add this >option with the name of the fileserver, or do I need to completely rework my >sendmail.cf to forward all local mail on to the server? If you were running a network of all Suns, with essentially unmodified Sun-supplied sendmail config files, and had everything set up the way they expect -- mail forwarding done by the aliases YP map, etc., then you would probably do well to just enable the R option and let it go at that. But if you are maintaining your own config files, you might well prefer to do without the R option, precisely because it's poorly documented and will frustrate you. You might not want it anyway, because it bypasses all of the output channel processing (like mailer-specific rewrite rules). Basically, it's an ugly hack. At any rate, it's not necessary -- you can do this without lots of changes to your existing config file. An added win is that this will work with other than Sun machines. Here's one way to do it: (based on diffs between my standalone config file and my client config file) MODS TO MAIL CLIENT'S CONFIG FILE: 1. Define a macro that evaluates to the domain name of your mail server, and another macro that evaluates to the domain name of your mail cluster. The first one is an actual machine name (i.e. it must have an IP address and a name server A record); the second is the name of your domain (it may have an A record or one or more MX records). The two may be the same if that's the way you have it set up. # NFS mail server (where /{usr,var}/spool/mail is mounted) DSmail-server.cs.utk.edu # mail cluster domain (common mail domain for all machines) DRcs.utk.edu 2. Typically, somewhere usually in ruleset 3 or ruleset 0, a config file has code recognize "local" domains and strip off the domain part. It might look something like this: R$*<@$j>$* $1<@>$2 strip off local domain Add a line here to recognize the "cluster" domain also, since they will end up at the same place. R$*<@$R>$* $1<@>$2 strip off cluster domain 3. Now, change whatever code calls the "local" mailer to instead call a different mailer. I use the name "server". The name "local" has some special connotations to sendmail -- it does alias expansion on names sent to this mailer (via /etc/aliases or the YP map), processes .forward files, recognizes special kinds of addresses (those starting with "/" or "|" or ":include:"), handles errors differently (many "permanent" errors to the local mailer are treated as temporary), looks up the user's full name, saves failed mail in dead.letter, and bounces mail if the user's name isn't in /etc/passwd or the YP passwd database. (Mostly because it fails trying to look at the user's .forward file -- else it would just let the delivery program return the error). Whew! Anyway, most of this processing is undesirable: you don't want aliasing or forwarding to take place because of all of the additional failure modes that crop up -- e.g. sendmail often doesn't handle either YP or NFS server failures correctly. Also, think about the case where you have a heterogeneous network and a user has his .forward file piping mail to a program in his/her private bin directory, which is compiled for a particular architecture...but if you only do this processing on the mail server, behavior is more predictable. Enough on why you shouldn't use the "local" mailer. BTW, you still need to have a mailer named "local", even though it will never be used. The last line in my ruleset zero looks like this: R$+ $# server $@ $S $: $1 4. I defined the "server" mailer as follows: Mserver, P=[IPC], F=AmnDMuXI, S=10, R=10, A=IPC $h, E=\r\n S10 # if the message is from root at the local domain, leave it alone # (Actually class T is a list of "daemon" user names that send out # logging messages -- it is helpful to be able to tell at a glance # which machine is complaining about something.) R$=T@$j $@$1@$j # if message from someone else is from local domain, change it to # the cluster domain R$*@$j $@$1@$R # otherwise, if it contains an '@' it's already fully qualified. R$*@$* $@$1@$2 # handle simple names (without '@') here # if from root, append our local domain name (not cluster name) R$=T $@$1@$j # otherwise, append cluster domain R$* $@$1@$R S20 # if it contains '@' assume it's already qualified R$*@$* $@$1@$2 # if it's to root, append local domain (not cluster) R$=T $@$1@$j # otherwise append cluster domain R$* $@$1@$R The main idea of the rewrite rules is to encourage everyone to send all mail to the domain associated with the "cluster", not of any individual machine. Otherwise you'll have to deal with the problem of how to handle mail to a machine whose name no longer exists. So while we *accept* mail for user@specific.machine, we rewrite outgoing mail as from user@cluster.domain, and the same is true for recipient addresses in message headers. Then replies will naturally be sent to the cluster domain, and people will get used to the idea that that's where your users get mail. On the other hand, if "root" on some machine sends a message to the sysadmin complaining about something that happened last night during a cron job, it's useful if the From: header tells you what machine it happened on. So we don't do this kind of processing for users like "root", "daemon", and "uucp". The "server" mailer desription doesn't have the 'F' flag set, and therefore will not generate a From: header if one was not supplied by the user agent. Fear not -- the mail server's sendmail will add one, and since it will recognize the mail as from a local user, it will do the passwd lookup and insert the user's full name. This produces headers like "From: Keith Moore <moore@cs.utk.edu>" instead of "From: moore@cs.utk.edu". Many user agents do supply from headers, in which case the setting of the 'F' flag is irrelevant. I also left off the 'p' flag, because I want the envelope from address to be <moore@some.domain> and not <@client.machine:moore@some.domain> I used to just send bare usernames to the "server" mailer, rather than qualifying them on the client (I think the Sun sendmail 'R' option does this), but it turned out to be easier to get everything right when the client machine presents a fully-qualified address to the server. 5. I added similar code to rewrite local user names in the tcp mailer's rewrite rules (also in the mail client's config file). MODS TO THE MAIL SERVER'S CONFIG FILE: 6. Now, the server needs some way to recognize all incoming mail. At my site, all of our addresses are of the form something.cs.utk.edu, but not all possible something's are mail clients. So I have a list of the something's in a file called /etc/MAIL-CLIENTS, and I define a class using that file: Fw/etc/MAIL-CLIENTS 7. Ruleset zero of the server config file has code to recognize mail to clients and treat it accordingly, along with mail to the server machine itself, and mail to the cluster domain: R$*<@$=w.$D>$* $1<@>$2 recognize mail to client domain R$*<@$R> $1<@>$2 recognize mail to cluster domain R$*<@$j> $1<@>$2 recognize mail to us ... R$*<@> $@$>0$1 retry after stripping @domain R<@>:$* $@$>0$1 retry after stripping @domain ... R$*<@$*>$* $# tcp $@ $2 $:$1$3 mail to other domains R$+ $# local $: $1 mail to local mailboxes 8. The server's rewrite rules for outgoing mail also make sure to rewrite local addresses as being at the cluster domain, not that of the server machine's domain name. (In our case, they are the same) 9. If your mail server is also the NFS file server for all of your users' home directories, that's about all you need to do. Otherwise you need to mount the home directories via either amd or automount, and replace your local, prog, and file mailers on the server with programs that can cope with unavailable file systems and return an exit status of EX_TEMPFAIL. My local mailer is just a shell script that makes a few sanity checks before calling /bin/mail. In practice it works quite well, but I will probably write a C version for the sake of efficiency. I'll send the complete set of sendmail config files (client, server, and standalone) along with the local mailer script, if you want them. Beware: they aren't as well commented as this message. Good luck, Keith Moore Internet: moore@cs.utk.edu University of Tenn. CS Dept. BITNET: moore@utkvx 107 Ayres Hall, UT Campus Telephone: +1 615 974 0822 Knoxville Tennessee 37996-1301 ``Friends don't let friends use YP (or NIS)''
nowicki@legato (Bill Nowicki) (09/22/90)
In article <9566@ur-cc.UUCP> Mark Sirota <msir@cc.rochester.edu> writes: >I'm told I need to use the 'R' option for this. The manual is pretty >useless on this, it says "Remote mode. Deliver through remote SMTP server. >Default is location of /var/spool/mail." > The idea is that you just need to put "OR" in the standard sendmail.cf file. This is the way it is shipped from Sun, and Sun has the exact same standard sendmail.cf file on thousands of systems. The "OR" will have no effect on the server that actually has the /var/spool/mail mailboxes on its physical disk. On machines that have /var/spool/mail mounted across the network using NFS, the rest of the rules in sendmail.cf will be ignored, and all mail will be delivered via the SMTP protocol (i.e. TCP over the network) to the file server from which /var/spool/mail is mounted. P.S. Although I designed and implemented this feature, I would not call the manual "useless". "Terse" perhaps. -- Bill Nowicki Legato Systems
spike@world.std.com (Joe Ilacqua) (09/28/90)
>Currently I use my own sendmail.cf, which is exactly the same for all <machines on our network. It does all delivery itself, rather than >forwarding on to a central mailhost. Now, for this new setup, I'm going to <want all local delivery to be done by the server, so that multiple machines >don't all go writing into the same file at the same time, right? Here is a cf for the clients that does just that. Works with Sun's 4.x sendmails and with 5.61 + IDA (should work with 5.6x but is untested) and probably other things too... ########################################################### # # SENDMAIL CONFIGURATION FILE FOR NFS CLIENTS. # # You should install this file as /etc/sendmail.cf # if want mail to appear to come from one central server # and not to be delivered localy. For ease of use, you # should then NFS mount the servers /usr/spool/mail on # the local /usr/spool/mail. # # All this cf does is change any reference to the local # hostname to the name of the server, and then send the # mail to the server. All other address parsing is handed # off to the server. # # I believe that this configuration functions correctly, however: # THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR # IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED # WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. # # Written by Spike (spike@world.std.com). Also check out his cool # Server cf. # my official hostname Dj$w # major relay mailer DMTCP # This is the name of the major relay so we can change our name. # For example: #DHcs.bu.edu DH ################################################# # # General configuration information # local domain name # For example: #Dmstd.com Dm # Version number of configuration file DVSpike-2.0 ### Standard macros # name used for error messages DnMailer-Daemon # UNIX header format DlFrom $g $d # delimiter (operator) characters Do.:%@!^=/[] # format of a total name #Dq$g$?x ($x)$. # This tends to get the Fullname added correctly Dq<$g> # SMTP login message De$j Sendmail $v/$V ready at $b ### Options # location of alias file OA/etc/aliases # default delivery mode (deliver in background) Odbackground # rebuild the alias file automagically OD # temporary file mode -- 0600 for secure mail, 0644 for permissive OF0600 # default GID Og1 # location of help file OH/usr/lib/sendmail.hf # log level OL9 # default messages to old style Oo # Cc my postmaster on error replies I generate OPPostmaster # queue directory OQ/tmp # read timeout for SMTP protocols Or15m # status file -- none OS/etc/sendmail.st # queue up everything before starting transmission, for safety Os # return queued mail after this long OT3d # default UID Ou1 ### Message precedences Pfirst-class=0 Pspecial-delivery=100 Pjunk=-100 ### Trusted users T root daemon uucp ### Format of headers H?P?Return-Path: <$g> HReceived: $?sfrom $s $.by $j ($v/$V) id $i; $b H?D?Resent-Date: $a H?D?Date: $a H?F?Resent-From: $q H?F?From: $q H?x?Full-Name: $x HSubject: H?M?Resent-Message-Id: <$t.$i@$j> H?M?Message-Id: <$t.$i@$j> HErrors-To: ########################### ### Rewriting rules ### ########################### # Sender Field Pre-rewriting S1 # None needed. # Recipient Field Pre-rewriting S2 # None needed. # Name Canonicalization # The magic to change the mail to make it look like it comes from the sever # machine. If the address contains no hostname or our hostname, we change it # to be the server hostname. $H is the name of the server machine... S3 R$*<$+>$* $2 basic RFC822 parsing R$- $@$1@$H user -> user@$H R$+@$+ $:$1@$[$2$] find real name (!CNAME) R$+@$=w $@$1@$H user@local -> user@$H R$+@$=w.$m $@$1@$H user@local.domain-> user@$H R$=w!$+ $@$2@$H local!user -> user@$H R$=w.$m!$+ $@$2@$H local.domain!user-> user@$H R@$=w:$+ $@@$H:$2 @local:something R@$=w.$m:$+ $@@$H:$2$3 @local.domain:something R$+%$=w $@$>3$1@$2 user%local R$+%$=w.$m $@$>3$1@$2 user%local.domain # We never deliver mail locally, so these are unused. How ever sendmail gets # unhappy if we don't have them... S4 # None needed Mlocal, P=/bin/mail, F=rlsDFMmnP, S=10, R=20, A=mail -d $u Mprog, P=/bin/sh, F=lsDFMeuP, S=10, R=20, A=sh -c $u S10 # None needed. S20 # None needed. ############################################################ ##### ##### Ethernet Mailer specification ##### ##### Messages processed by this configuration are assumed to remain ##### in the same domain. This really has nothing particular to do ##### with Ethernet - the name is historical. MTCP, P=[IPC], F=msDFMuCX, S=11, R=21, A=IPC $h S11 # None needed. S21 # None needed. ##### RULESET ZERO PREAMBLE S0 # On entry, the address has been canonicalized and focused by ruleset 3. # Punt to mail server R$+ $#$M $@$H $:$1 -- "The World" - Public Access Unix - +1 617-739-9753 24hrs {3,12,24}00bps
rsalz@bbn.com (Rich Salz) (09/29/90)
>forwarding on to a central mailhost. Now, for this new setup, I'm going to >want all local delivery to be done by the server... ### ### SENDMAIL CONFIGURATION FILE ### This is the sendmail.cf for a client who can make a TCP connection to ### a mail relay. No local mail happens here. Sendmail is not run in ### daemon mode, either, just hourly out of cron to pick up anything ### left when the server is not reachable. ### ## HOSTNAME MACROS AND CLASSES ## The name of our corporate domain. DCbbn.com ## The official name of this host (from gethostname(2)). Dj$w ## The relay host where everything gets forwarded to. DRpineapple.bbn.com ## GENERAL CONFIGURATION INFORMATION ## Stuff here is required and reflects some policy decisions. ## SMTP login message. De$j Sendmail $v/$V ready at $b; how did you get here? ## Format of the UNIX from line -- essentially a constant. DlFrom $g $d ## Name to use for returned mail -- essentially a constant. DnMAILER-DAEMON ## Token delimeters -- word separators in the rewrite rules below. Do.:%@![] ## Format of a sender's address; use full name. Dq$x <$g> ## Version of this .cf file. DVrsalz-13-nov-89 ## Location of the alias file. OA/usr/lib/aliases ## Default delivery mode (one of background, foreground, queue). Odbackground ## Permissions for any temporary files we create. OF0644 ## Default group id for mailers to run under. Og1 ## Location of the SMTP help file. OH/dev/null ## Logging level. OL9 ## Send to sender if an alias expansion includes her (a/k/a "me too")? OmT ## Allow headers to be in old style (i.e., spaces delimit names)? OoT ## Where to send important error messages. OPpostmaster ## Location of the queue directory. OQ/usr/spool/mqueue ## Give up on connections after this long a time period. Or2h ## Queue up everything before starting transmission? OsT ## How long message can sit in queue before it's bounced back? OT3d ## Default user id for mailers to run under. Ou1 ## Password to enter wizard/debug mode. OW* ## Message precedences. Pfirst-class=0 Pspecial-delivery=100 Pbulk=-50 Pjunk=-100 ## Trusted users -- these people can fake headers. Troot ## Format of headers. HReceived: $?sfrom $s $.by $j id <$i@$j>; $b HDate: $a HFrom: $q HMessage-Id: <$t.$i@$j> HDResent-Date: $a HFResent-From: $q HMResent-Message-Id: <$t.$i@$j> ## REWRITING RULES ## ## These are the rules used for the following fields: ## From 3 -> 1 -> 4 -> 3 -> 1 -> S -> 4 ## To 3 -> 0 -> 4 ## From: 3 -> 1 -> 5 -> 4 ## To: 3 -> 2 -> R -> 4 ## where S and R stand for the mailer-specific rewrite rules named in ## the mailer definition. ## ## RULESET 0 -- Pick a mailer. S0 R$*<$*>$* $1$2$3 defocus R$+ $:$>3$1 make canonical R$*<@[$+]>$* $#relay$@[$2]$:$1@[$2]$3 numeric internet spec R$*<$*.>$* $1<$2>$3 drop trailing dot R<@>:$* $@$>0$1 retry after route strip R$*<@> $@$>0$1 strip null trash & retry ## Machine dependent part of ruleset 0. ## Here is where we actually find a mailer to invoke. R$* $#relay$@$R$:$1 forward everything ## ## RULESET 1 -- From and From: fields. S1 ## ## RULESET 2 -- To: field. S2 ## ## RULESET 3 -- Basic name canonicalization. S3 # Handle the SMTP "from:<>" as a special case. R<> $@@ turn into magic token # Basic textual canonicalization. R$*<$+>$* $2 basic RFC821/822 parsing R$*<$*>$* $1$2$3 in case recursive # Make sure <@a,@b,@c:u@d> syntax is easy to parse -- undone later. R@$+,$+ @$1:$2 change all "," to ":" # Localize and dispose of domain-based addresses. R@$+:$+ $@$>6<@$1>:$2 handle <route-addr> R$+:$*;@$+ $@$1:$2;@$3 list syntax R$+@$+ $:$1<@$2> focus on domain R$+<$+@$+> $1$2<@$3> move gaze right R$+<@$+> $@$>6$1<@$2> already canonical # Convert old-style addresses to a domain-based address. R$+%$+ $@$>6$1<@$2> u%h R$-!$+ $@$>6$2<@$1.UUCP> resolve uucp names ## ## RULESET 4 -- Final output rewriting. S4 R@ $@ handle <> error addr # Externalize local domain info. R$*<$*LOCAL>$* $1<$2$R>$3 change local info R$*<$+>$* $1$2$3 defocus R@$+:$+:$+ $@@$1,$2:$3 <route-addr> canonical R$+<@$w> $1 remove our name R$+@$-.UUCP $2!$1 u@h.UUCP->h!u ## ## RULESET 5 -- From: field post-processing (just before final). S5 ## ## RULESET 6 -- Canonicalize hostname (called from ruleset 3). S6 R$+<@$+.$+.UUCP> $1<@$2.$3> u@h.d.uucp->u@h.d ## ## RULESET 14 -- All fields for all mailers S14 ## MAILER SPECIFICATIONS ## ## local; an error as we do no mail delivery here Mlocal, P=/usr/lib/sendmail, F=DFILMmsuX, S=14, R=14, A=sendmail $n ## prog; an error as we do no mail delivery here Mprog, P=/usr/lib/sendmail, F=DFILMmsuX, S=14, R=14, A=sendmail $n ## relay; connect to Sendmail on relay host. Mrelay, P=[IPC], F=DFLMmsuX, S=14, R=14, A=IPC $h, E=\r\n -- Please send comp.sources.unix-related mail to rsalz@uunet.uu.net. Use a domain-based address or give alternate paths, or you may lose out.