Feizhou wrote:
In above example u can see in the 1st example the
sender(xyz) is not real user of my domain , still he
is able to sendmail to my real users (abhi).
plz help me.
abhishek singh,
The simplest way that I can think of is to create a database of your
addresses and then check the mail from against that database and reject
if not found.
The problem is how to maintain that database.
You could add a table lookup for this database and then add rules in
Local_check_mail to check mail from: addresses against the database.
in /etc/mail, create a file realuser
eg:
cat realuser
root OK
chris OK
makemap hash realuser.db < realuser
Make a copy of sendmail.cf (eg: test-sendmail.cf) and add a lookup for
realuser.db:
Krealuser hash -o /etc/mail/realuser.db
Add some rulesets to check the mail from against this database:
SLocal_check_mail
R< $- @ domain.com > tabspace $: < $(realuser $1 $: ? $) >
R< $- @ $* > tabspace OK
R< OK > tabspace OK
R<?> tabspace $#error $@ 5.7.1 $: "550 Access denied"
NB: REPLACE domain.com with your real domain. sendmail rulesets have
left and right hand sides separated by tabs. Please make sure you have
them when you copy for testing. If you have more than one domain, then
add more R< $- @ domain.com > tabspace $: < $(realuser $1 $: ? $) >
rules BEFORE the R< $- @ $* > tabspace OK line. Sorry for this as
this is just a quick hack.
You can test offline by:
'sendmail -bt -C test-sendmail.cf'
Some likely output below:
==run check on external address==
> check_mail <dunno@xxxxxxxxx>
check_mail input: < dunno @ yahoo . com >
Local_check_mail input: < dunno @ yahoo . com >
Local_check_mail returns: OK
Basic_check_mail input: < dunno @ yahoo . com >
tls_client input: $| MAIL
D input: < > < ? > < ! "TLS_Clt" > < >
D returns: < ? > < > < ? > < ! "TLS_Clt" > < >
A input: < > < ? > < ! "TLS_Clt" > < >
A returns: < > < ? > < ! "TLS_Clt" > < >
TLS_connection input: $| < > < ? > < ! "TLS_Clt" > < >
TLS_connection returns: OK
tls_client returns: OK
CanonAddr input: < dunno @ yahoo . com >
canonify input: < dunno @ yahoo . com >
Canonify2 input: dunno < @ yahoo . com >
Canonify2 returns: dunno < @ yahoo . com . >
canonify returns: dunno < @ yahoo . com . >
Parse0 input: dunno < @ yahoo . com . >
Parse0 returns: dunno < @ yahoo . com . >
CanonAddr returns: dunno < @ yahoo . com . >
SearchList input: < + From > $| < F : dunno @ yahoo . com > < U
: dunno @ > < D : yahoo . com > < >
F input: < dunno @ yahoo . com > < ? > < + From > < >
F returns: < ? > < >
SearchList input: < + From > $| < U : dunno @ > < D : yahoo .
com > < >
U input: < dunno @ > < ? > < + From > < >
U returns: < ? > < >
SearchList input: < + From > $| < D : yahoo . com > < >
D input: < yahoo . com > < ? > < + From > < >
D input: < com > < ? > < + From > < >
D returns: < ? > < >
D returns: < ? > < >
SearchList returns: < ? >
SearchList returns: < ? >
SearchList returns: < ? >
Basic_check_mail returns: < OKR >
check_mail returns: < OKR >
==run check on existing address==
> check_mail <chris@xxxxxxxxxx>
check_mail input: < chris @ domain . com >
Local_check_mail input: < chris @ domain . com >
Local_check_mail returns: OK
Basic_check_mail input: < chris @ domain . com >
tls_client input: $| MAIL
D input: < > < ? > < ! "TLS_Clt" > < >
D returns: < ? > < > < ? > < ! "TLS_Clt" > < >
A input: < > < ? > < ! "TLS_Clt" > < >
A returns: < > < ? > < ! "TLS_Clt" > < >
TLS_connection input: $| < > < ? > < ! "TLS_Clt" > < >
TLS_connection returns: OK
tls_client returns: OK
CanonAddr input: < chris @ domain . com >
canonify input: < chris @ domain . com >
Canonify2 input: chris < @ domain . com >
Canonify2 returns: chris < @ domain . com . >
canonify returns: chris < @ domain . com . >
Parse0 input: chris < @ domain . com . >
Parse0 returns: chris < @ domain . com . >
CanonAddr returns: chris < @ domain . com . >
SearchList input: < + From > $| < F : chris @ domain . com > < U
: chris @ > < D : domain . com > < >
F input: < chris @ domain . com > < ? > < + From > < >
F returns: < ? > < >
SearchList input: < + From > $| < U : chris @ > < D : domain .
com > < >
U input: < chris @ > < ? > < + From > < >
U returns: < ? > < >
SearchList input: < + From > $| < D : domain . com > < >
D input: < domain . com > < ? > < + From > < >
D input: < com > < ? > < + From > < >
D returns: < ? > < >
D returns: < ? > < >
SearchList returns: < ? >
SearchList returns: < ? >
SearchList returns: < ? >
Basic_check_mail returns: < OKR >
check_mail returns: < OKR >
==run check on fake local address==
>check_mail <dunno@xxxxxxxxxx>
check_mail input: < dunno @ domain . com >
Local_check_mail input: < dunno @ domain . com >
Local_check_mail returns: $# error $@ 5 . 7 . 1 $: "550 Access denied"
check_mail returns: $# error $@ 5 . 7 . 1 $: "550 Access denied"
==hit CTRL-D to leave sendmail ruleset debugging mode==
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