Seed URLs are rejected

[denkv]

I set the following seed:

seed/seeds.csv:

uri,type
http://a.b.c.d:8000/,html

(a.b.c.d is an IP address)

I get this in logs:

frontier | [main] INFO  [o.d.s.c.SeedConfiguration] - <SEED_FILE found, will use seed file to initialize frontier...>
frontier | [main] WARN  [o.d.s.f.i.FrontierImpl   ] - <addNewUri(CrawleableUri("a.b.c.d",,UNKNOWN)): null is not supported, only [http, https]. Will not added!>