reverse name lookups

Hi folks,

Simple question... how to do a reverse name lookups with qmail ?

This is for return mail / bounce from system to sender.

TIA

PD

On 20 Feb 2004 01:22:31 -0800, Paul Darius <paul@spc.co.id> may have written:
>
> Simple question... how to do a reverse name lookups with qmail ?
>
> This is for return mail / bounce from system to sender.

I am not sure what you mean by this? qmail itself should never need to
do a reverse lookup. tcpserver will do reverse lookups of incoming
connections and set an environment variables called TCPREMOTEHOST.

What problem are you trying to solve?

--
Brian T Glenn
delink.net Internet Services

> I am not sure what you mean by this? qmail itself should never need to
> do a reverse lookup. tcpserver will do reverse lookups of incoming
> connections and set an environment variables called TCPREMOTEHOST.
>
> What problem are you trying to solve?

To reject emails from non existing domain. We received a lot of emails
from non existing domain to non existing address @ our domains.

Regards

PD

On 22 Feb 2004 19:19:24 -0800, Paul Darius <paul@spc.co.id> wrote:
>> I am not sure what you mean by this? qmail itself should never need to
>> do a reverse lookup. tcpserver will do reverse lookups of incoming
>> connections and set an environment variables called TCPREMOTEHOST.
>>
>> What problem are you trying to solve?
>
> To reject emails from non existing domain. We received a lot of emails
> from non existing domain to non existing address @ our domains.
>
> Regards
>
> PD

this is patch against netqmail-1.05.
if file control/mfcheck or env var MFCHECK has number 0,
no checks are done.


--- netqmail-1.05/qmail-smtpd.c.bak 2004-02-09 19:38:08.000000000 +0200
+++ netqmail-1.05/qmail-smtpd.c 2004-02-09 20:00:52.000000000 +0200
@@ -23,9 +23,11 @@
#include "timeoutread.h"
#include "timeoutwrite.h"
#include "commands.h"
+#include "dns.h"

#define MAXHOPS 100
unsigned int databytes = 0;
+unsigned int mfchk = 0;
int timeout = 1200;

int safewrite(fd,buf,len) int fd; char *buf; int len;
@@ -50,6 +52,8 @@ void die_ipme() { out("421 unable to fig
void straynewline() { out("451 See http://pobox.com/~djb/docs/smtplf.html.\r\n"); flush(); _exit(1); }

void err_bmf() { out("553 sorry, your envelope sender is in my badmailfrom list (#5.7.1)\r\n"); }
+void err_hmf() { out("553 sorry, your envelope sender domain must exist (#5.1.8)\r\n"); }
+void err_smf() { out("451 temporary DNS error while resolving envelope sender domain (#4.7.0)\r\n"); }
void err_nogateway() { out("553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)\r\n"); }
void err_unimpl(arg) char *arg; { out("502 unimplemented (#5.5.1)\r\n"); }
void err_syntax() { out("555 syntax error (#5.5.4)\r\n"); }
@@ -112,6 +116,10 @@ void setup()

if (rcpthosts_init() == -1) die_control();

+ if (control_readint(&mfchk, "control/mfcheck") == -1) die_control();
+ x = env_get("MFCHECK");
+ if (x) { if (scan_ulong(x, &u)) mfchk = u; }
+
bmfok = control_readfile(&bmf,"control/badmailfrom",0);
if (bmfok == -1) die_control();
if (bmfok)
@@ -208,6 +216,27 @@ int bmfcheck()
return 0;
}

+int mfcheck(ips)
+int *ips;
+{
+ static stralloc sa_mf = {0};
+ static ipalloc ia_mf = {0};
+ int j;
+
+ if (ips) *ips = 0;
+ if (!mfchk || (addr.len == 1)) return 0;
+ j = byte_rchr(addr.s, addr.len, '@') + 1;
+ if (j < addr.len) {
+ if (!stralloc_copys(&sa_mf, addr.s + j)) die_nomem();
+ j = dns_mxip(&ia_mf, &sa_mf, 1);
+ if (ips) *ips = ia_mf.len;
+ if ((j == 0) && (ia_mf.len == 0)) return DNS_HARD;
+ return j;
+ } else {
+ return 0;
+ }
+}
+
int addrallowed()
{
int r;
@@ -239,8 +268,24 @@ void smtp_rset(arg) char *arg;
}
void smtp_mail(arg) char *arg;
{
+ int ips;
+
if (!addrparse(arg)) { err_syntax(); return; }
flagbarf = bmfcheck();
+ switch(mfcheck(&ips)) {
+ case DNS_HARD:
+ err_hmf();
+ return;
+ case 1:
+ /* resolved at least one IP? */
+ if (ips > 0) break;
+ case DNS_SOFT:
+ case DNS_MEM:
+ err_smf();
+ return;
+ default:
+ break;
+ }
seenmail = 1;
if (!stralloc_copys(&rcptto,"")) die_nomem();
if (!stralloc_copys(&mailfrom,addr.s)) die_nomem();


--
Safari - y7pt9001@sneakemail.com.gov.invalid - Reply-To to reply (remove 'ies')
http://eth1.promisc.us/aestrap.html

> > To reject emails from non existing domain. We received a lot of emails
> > from non existing domain to non existing address @ our domains.
> >
> > Regards
> >
> > PD
>
> this is patch against netqmail-1.05.
> if file control/mfcheck or env var MFCHECK has number 0,
> no checks are done.
>
Could you please to advice an example of :
+ MFCHECK env and where to put ?
+ control/mfcheck file ?

Regards

PD

On 24 Feb 2004 01:51:17 -0800, Paul Darius <paul@spc.co.id> wrote:
>> > To reject emails from non existing domain. We received a lot of emails
>> > from non existing domain to non existing address @ our domains.
>> >
>> > Regards
>> >
>> > PD
>>
>> this is patch against netqmail-1.05.
>> if file control/mfcheck or env var MFCHECK has number 0,
>> no checks are done.
>>
> Could you please to advice an example of :
> + MFCHECK env and where to put ?

well well, if you use tcpserver, -x option specifies the cdb file to use,
here example line for tcprules:
10.20.30.40:allow,RELAYCLIENT="",MFCHECK="0"

docs are here
http://cr.yp.to/ucspi-tcp.html

> + control/mfcheck file ?

echo 1 > /var/qmail/control/mfcheck
(make sure permissions are OK)

MFCHECK env var overrides control/mfcheck.

> Regards
>
> PD

--
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