$TTL 259200	; 3 days
2.168.192.IN-ADDR.ARPA.		IN SOA	sercentos7.curso.esp. root.curso.esp. (
				2021022501 ; serial
				86400      ; refresh (1 day)
				7200       ; retry (2 hours)
				2592000    ; expire (4 weeks 2 days)
				172800     ; minimum (2 days)
				)
2.168.192.IN-ADDR.ARPA. 	NS	orion.curso.esp.
2.168.192.IN-ADDR.ARPA. 	NS	sercentos7.curso.esp.
2.168.192.IN-ADDR.ARPA. 	MX	3 sercentos7.curso.esp.

150               IN      PTR     trasgu.curso.esp.
5                 IN      PTR     sercentos7.curso.esp.
152 		  IN      PTR     orion.curso.esp.	
8                 IN	  PTR     pc2.curso.esp.