Combine two table in a new one

I have two tables in a Postgres , table 1 with hosts, ips and severity, and table 2 with geo localization of each networks. I need to create a table 3 with all data of the table 1 and comparing the host (table 1) with network from table 2 to add on table 1 de column site, how can I do this.

TABLE 1     
HOST        |     IP            | SEVERITY
HOST - 1    | 172.2.36.2        |   7
HOST - 2    | 172.2.34.35       |   7
HOST - 3    | 172.2.36.9        |   8
HOST - 4    | 172.2.34.77       |   6
HOST - 5    | 172.2.36.2        |   5
HOST - 6    | 172.2.36.99       |   3
HOST - 7    | 172.2.34.55       |   4


TABLE 2 
NETWORK     | SITE
172.2.36.   | SITE A
172.2.34.   | SITE B


TABLE 3     (NEW)   
HOST        | IP            | SEVERITY  |   SITE
HOST - 1    | 172.2.36.2    |   7       |  SITE A
HOST - 2    | 172.2.34.35   |   7       |  SITE B
HOST - 3    | 172.2.36.9    |   8       |  SITE A
HOST - 4    | 172.2.34.77   |   6       |  SITE B

Table 1

Table 2

Table Result

Thanks