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Mikhail T.
Asked: 2017-07-27 19:42:37 +0800 CST

How to make sendmail respect +-notation for virtual users?

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I have different forwarding needs for different domains, which all point to my mail-server:

user1@example.com   foo@example.org
user2@example.com   bar@example.net
@example.com        mylocalaccount

This all works... However, some of these users wish to use the +-notation to give different vendors different addresses, such as user1+vendor@example.com. And this part is not working -- all such e-mails end up delivered to the catchall mylocalaccount instead of being forwarded properly.

How do I make user+foo@example.com be forwarded to the same destination as user@example.com?

I tried adding entries like

user1+*@example.com    foo+%2@example.org

but that didn't fix the problem...

Here are the debug-traces:

Without the detail:

% sendmail -d60.5 -bv g@example.com
map_lookup(dequote, me, %0=me) => NOT FOUND (0)
map_lookup(dequote, g, %0=g) => NOT FOUND (0)
map_lookup(virtuser, g@example.com, %0=g@example.com, %1=g) => gexample@example.net (0)

... works.

With the detail:

% sendmail -d60.5 -bv g+meow@example.com
map_lookup(dequote, me, %0=me) => NOT FOUND (0)
map_lookup(dequote, g+meow, %0=g+meow) => NOT FOUND (0)
map_lookup(virtuser, g+meow@example.com, %0=g+meow@example.com, %1=g+meow) => NOT FOUND (0)
map_lookup(virtuser, @example.com, %0=@example.com, %1=g+meow) => me (0)
map_lookup(dequote, me, %0=me) => NOT FOUND (0)
map_lookup(user, me, %0=me) => me<> (0)
g+meow@example.com... deliverable: mailer local, user me

... does not work -- comes to the catch-all local account "me".

sendmail

2 Answers

  1. If you want to virtusertable to redirect with +detail preserved then try:

    # use %2 if you want to strip EMPTY +detail (user+@example.net)
user1@example.com   foo%3@example.org

    Debug procedure
    As root execute sendmail -d60.5 -bv user1+x@example.net.
    It should trace map lookups including virtusertable map lookups.
    Try sendmail -d21.12 -d60.5 -bv user1+x@example.net if +detail is stripped before virtusertable lookups.

    user1+detail@example.com by default should make sendmail look for the following virtusertable enries:

    1. user+detail@example.com
    2. user++@example.com
    3. user+*@example.com
    4. user@example.com
    5. ++@example.com
    6. +*@example.com
    7. @example.com

    user+@example.com (plus present but detail empty) conducts lookups 1+3+4+6+7
    user@example.com (no +detail present) condutcs lookups 4+7

    • 1
  2. Best Answer

    It seems that + is missing in OperatorChars in your sendmail.cf. It makes R lines in sedmail.cf see one token user+detail instead of three tokens user + detail.

    sendmail.cf generated from sendmail.mc should set OperatorChars to .:%@!^/[]+ by default accoding to the bat book. It may be changed in mc file by defining confOPERATORS.

    Check what is reported by grep OperatorChars /etc/mail/sendmail.cf

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