Why can't connections from the server be closed?

Question

linux

I have a fairly large number of http connections to external systems, recently connections from one IP have begun to accumulate.
tcp 0 0 ip1:40117 ip2:80 ESTABLISHED 22902/go
Because of this, the number of open connections has increased by 10-20 times on the server, hence the limits on open files and a lot of problems.
Questions two as the external system does so that connections were not closed?
How to solve the problem without disturbing work with other connections.

Answer 1

https://ru.wikipedia.org/wiki/%D0%9F%D0%BE%D1%81%D...