Am So, den 15.08.2004 schrieb Harry Putnam um 2:59: sendmail2.mc Is newsguy.com your domain? I ask because of the central and important comment on masquerading from the cf/README: "The masquerade name is not normally canonified, so it is important that it be your One True Name, that is, fully qualified and not a CNAME. However, if you use a CNAME, the receiving side may canonify it for you, so don't think you can cheat CNAME mapping this way." (http://www.sendmail.org/m4/masquerading_relaying.html) It makes not much sense to offer a smart host which requires a resolvable FQDN. How should people at home with DSL, modem or ISDN connection mail throught their ISP's smart host? It is the task of the ISP's smart host to jump into this gap and offer such linked users the ability to use their own MTA without the risk that many if not most of the recipient MTAs reject mail coming from them, just because they have no resolvable FQDN. Whether the contacting host announces himself with a resolvable FQDN at HELO/EHLO depends from settings of the real hostname, the domain name (if set in sendmail.mc) and from masquerading settings (if are defined). Genericstable does only rewrite the sender envelope address. Important is that your bogus (internal) FQDN is internally resolvable. Using a --> GENERICS_DOMAIN(`local.net0')dnl belongs to the set, else the genericstable feature would not know for which domains to look for rewriting. Maybe my misunderstanding at this point and just to clear out: if you only change map files (the text files from which hashes/.db files are generated) you do not need to restart Sendmail. That is one sense of using these hash files. A Sendmail daemon restart is only necessary if you change the central configuration files ending with .cf (sendmail.cf and submit.cf) and after changes on pure text files like local-host-names, generics-domains or trusted-users. Please check what following prints out: echo "$=M" | /usr/lib/sendmail -bt -d0 echo "$=G" | /usr/lib/sendmail -bt The hosts file looks perfect. [ ... ] [ ... ] [ ... ] [ ... ] [ ... ] There is missing: MASQUERADE_DOMAIN(`localhost')dnl MASQUERADE_DOMAIN(`localhost.localdomain')dnl MASQUERADE_DOMAIN(`reader.local.net0')dnl Both commands from above for class{M} and class{G} have to show proper settings. Alexander -- Alexander Dalloz | Enger, Germany | GPG key 1024D/ED695653 1999-07-13 Fedora GNU/Linux Core 2 (Tettnang) kernel 2.6.7-1.494.2.2smp Serendipity 04:49:12 up 10 days, 22:16, load average: 0.22, 0.27, 0.39

On Sun, 2004-08-15 at 08:59, Harry Putnam wrote: What exactly does genericstable do? (Sorry, writing this mail off-line) But it isn't right? newsguy.com isn't a valid Domain Name is it?? I'm not sure if your solution is a viable solution to my problem. My Problem. @work = mails must be sent out using the corp exhange server (smart host feature _must_ be implemented via sendmail.mc) @home = mails are sent out w/o using smart host. Meaning, I have to actively re-compile sendmail.mc each time between office and home to send out emails. Cause @home, mails gets relayed directly to the receipient's MX. Just as I thought. And what/how does this affect mail sending? What does this achieve? I don't see a genericstable in my /etc/mail/ directory What's data format error? And I see that your relay is = smtp.newsguy.com, which resolves to your Inet Public IP. For my case, it gets relayed to the localhost (127.0.0.1)'s smtp. which then hands it over to sendmail to contact the MX. What I want to know is, is there a way to say that I want mails to be sent out 1st using the Direct approach, if it fails then fall back to the smart host. Something like /etc/host.conf user$ cat host.conf order hosts,bind pseudo code : if [check if it's a local address ]; then pass to local sendmail elif [check if we can send direct to MX ] pass to sendmail for direct MX else # when all else fails pass to smart host for relay -- Ow Mun Heng Fedora GNU/Linux Core 2 on D600 1.4Ghz CPU kernel 2.6.7-2.jul1-interactive Neuromancer 15:00:10 up 24 min, 5 users, load average: 0.42, 0.40, 0.36

Am So, den 15.08.2004 schrieb Ow Mun Heng um 12:19: Please read my explanations in the posting I just wrote for Harry. You use the same email address @wdc.com from work too at home? Can you use the business mail server as smart host as well from at home (SMTP AUTH)? It will lead to rejects by foreign MTAs. For SPAM fighting most MTAs meanwhile don't accept mail with 'faked' sender addresses. You have to create a genericstable your own, if you like to use that one. For each domain in class {G} - the generics-domains listing is missing here - the sender address on the left side in the genericstable map file is rewritten to what is to be found on the right hand side. smtp.newsguy.com is Harry's ISP's smart host MTA. Yes, this is part of communication between Harry's Sendmail and the smart host. If I remember correctly there is no such fallback order. Do you use different mail addresses at work and at home? Then you could use smarttable. Else I would suggest not using the smart_host definition in the sendmail.mc file, but to use the mailertable instead. That makes switching a bit easier: you don't need to restart the Sendmail daemon because you don't change the sendmail.mc/.cf file but the mailtertable hashed map file: edit the mailertable file and run "make -C /etc/mail" and your change takes place immediately. See http://www.sendmail.org/m4/mailertables.html on how to set the entry for your smart host. To deactivate simply put a # in front of it to directly speak to the recipient MTAs. Alexander -- Alexander Dalloz | Enger, Germany | GPG key 1024D/ED695653 1999-07-13 Fedora GNU/Linux Core 2 (Tettnang) kernel 2.6.7-1.494.2.2smp Serendipity 20:18:18 up 12 days, 13:45, load average: 0.16, 0.18, 0.12

Ok Henry, let me start a new path through all the confusion (I think I did some mis-expressing meanwhile in both threads about this topic). Both, masquerade and genericstable, have the same purpose: to rewrite the sender envelope mail address. Whether masquerading is preferable or genericstable depends on the specific situation. It is possible to mix both, from my own testing I see that a genericstable rewriting overrides masquerade settings. 1) masquerading You define the @FQDN rewrite address with MASQUERADE_AS(`FQDN') which will rewrite the mail from the host itself and all in class {M} to have a header address coming from there. To make sure the envelope address is properly set too, there is the FEATURE(masquerade_envelope) instruction. To not only masquerade the single mail host itself but all hosts inside the net, you can use FEATURE(masquerade_entire_domain). MASQUERADE_DOMAIN(foo) fill the class{M}. The masquerading (mail header and envelope) sender address rewriting takes place as long the sender address (@domain-part) previous to rewriting is something inside the class {M}. If the sender chooses an address in his mail client which is different from anything in class {M} no rewriting is done by masquerading. On the other hand, mail sending using mail or sendmail (without parameter -f) from the masq host itself or any masqueraded other will lead to address rewriting. 2) genericstable The FEATURE(genericstable) is a (hashed) map file with on the LHS (left hand side) has the user or address which shall be rewritten and on the RHS (right hand side) the address to which the LHS shall be converted. class {G} is empty by default and is filled by entries placed into the plain test file generics-domains. FEATURE(generics_entire_domain) is the parallel to FEATURE(masquerade_entire_domain). How it works: if mail is processed and the FEATURE(genericstable) is active, then the @domain-part is looked up in class {G} whether it is to be rewritten. If the @domain-part is part of class {G} then the genericstable map file is taken and searched for a matching LHS part. If none found nothing happens, if an entry found the address is rewritten with the content of the RHS. 3) When address rewriting is needed When you run your own Sendmail and you have no public resolvable FQDN for that mail host, assigned the FQDN to your IP address using an DNS record, you need address rewriting for those cases where the origin mail address will be the private, non resolvable domain address. Examples for this are notification mails sent out by cronjobs or "hand made" mail using the "mail" command. Mail clients setting the envelope sender address correctly, you do not need masquerading or genericstable rewriting. Using the smart host of your ISP or from any other service does not heal this situation. Though it is recommended to use such a smart host from dial-in homed connections because otherwise your Sendmail (fits for other MTAs as well) will directly deliver to the recipient's MTA, and meanwhile many of those do not accept incoming connections by dial-up IPs (because of need for anti SPAM fighting). The smart host does not rewrite the sender address, but it should reject attempts to relay, when he (the smart host) acknowledges a public non-existent domain part in the sender's mail address. 4) example setup Given your Sendmail host name is satyr.local.net0 and you send mail through it, either locally or from a host in the same private net (IP, name does not need to be the same) using your Sendmail for sending, and you do not use a mail client which sets a proper (proper because public existing and deliverable) mail address, then you need address rewriting either with masquerading or genericstable. Let us take the masquerading setup. MASQUERADE_AS(`newsguy.com')dnl FEATURE(masquerade_envelope)dnl This is what you did use. If newsguy.com is your controlled domain, it is not big problem, because you can create valid email addresses for that domain for each sender you use through your Sendmail. It is then a problem, if you for example have only 1 email address like hputnam(a)newsguy.com but no other. Why? Well, imagine the case mail is sent out by a root's cronjob. You know how it is rewritten? Yes, to root(a)newsguy.com. Where does a reply could go? Right, not to the sender. Same is valid for all other cases where the mail is not initiated by your local user with name hputnam. In your last mail you wrote you used (at least tested with) MASQUERADE_AS(`whizbang.net') address rewriting and that it succeeded when sending through your ISP's smart host. It of course worked, rather than sending with an address of @satyr.local.net0, because whizbang.net is a public resolvable thus valid domain name (does not matter whether a mail server runs for it). So the smart host verifies it is existing and accepts it for relaying. Of course your mail sent out has now the sender address hputnam(a)whizbang.net what you hardly want. If you would use for the MASQUERADE_AS name `whozbang.net' your ISP's smart host would reject the relay attempt. Address rewriting using genericstable would work similar in your case, you only have to respect the differences. Especially the differences may lead to the decision to give genericstable the preference over masquerading, because when using masquerading you won't get an error when sending with a non existing email address while rewriting to `newsguy.com' (not your domain as you said before) for example. With genericstable you have to define positive cases, where a rewriting has to take place. And in each case not rewrite target is found you or a script sending out with a non rewritten mail address will cause an error immediately. I really hope my explanations do not cause a lot more confusion and questions :) But feel free to ask. Alexander -- Alexander Dalloz | Enger, Germany | GPG key 1024D/ED695653 1999-07-13 Fedora GNU/Linux Core 2 (Tettnang) kernel 2.6.7-1.494.2.2smp Serendipity 18:58:51 up 12 days, 12:26, load average: 0.35, 0.47, 0.45