Migrating from 8.2 to 9.1 : invalid port number

Hi all,

in my production environment I have Postgresql 8.2 + PgPool. The port number I specify in PgPool configuration is not a real portnumber (e.g. 123456). I can define a "dblink" as :

dblink('dbname=XXXX host=/var/run port=123456 user=XXXX password=XXXX'::text, 'select ... '::text) t1( ... );

or start "psql" as:

psql -U XXXX -h /var/run -p 123456 XXXX

without problems. In my development environment I upgraded to 9.1 version and the result is:

invalid port number: "123456"

in both cases. Does Postgresql 9.1 check the "port number" value although I'm connecting through a "Unix domain socket"? Is it a bug or an intended behavior?
I noticed that it accepts values up to 65535 .

Thanks in advance

Alberto