unable to reach bsd-lists via mail

[Christopher J. Ruwe]

I have a problem with my mail-server configuration so that mail sent
will not reach any freebsd adresses. The solutions offered in similar
mails already accessible via various archives did not help :-( 

I usually send mail from the domain cruwe.de with the mail-server
mail.cruwe.de.

My configration is as such, that

$ host cruwe.de
cruwe.de has address 188.40.164.98
cruwe.de mail is handled by 10 mail.cruwe.de.

and

$ host mail.cruwe.de
mail.cruwe.de has address 188.40.164.98
mail.cruwe.de mail is handled by 10 mail.cruwe.de.

Now,

$ dig cruwe.de

; <<>> DiG 9.6.3 <<>> cruwe.de
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32046
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;cruwe.de.                      IN      A

;; ANSWER SECTION:
cruwe.de.               300     IN      A       188.40.164.98

;; Query time: 73 msec
;; SERVER: 192.168.2.1#53(192.168.2.1)
;; WHEN: Sat Jun 18 17:51:14 2011
;; MSG SIZE  rcvd: 42

is right and

[chris at dijkstra:~]$ dig -x 188.40.164.98

; <<>> DiG 9.6.3 <<>> -x 188.40.164.98
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40136
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;98.164.40.188.in-addr.arpa.    IN      PTR

;; ANSWER SECTION:
98.164.40.188.in-addr.arpa. 267 IN      PTR     cruwe.de.

;; Query time: 10 msec
;; SERVER: 192.168.2.1#53(192.168.2.1)
;; WHEN: Sat Jun 18 17:51:48 2011
;; MSG SIZE  rcvd: 66

seems to be OK.

Does anyone have an idea what could be the issue?

Thank you, cheers
-- 
Christopher J. Ruwe
TZ GMT + 2