今の2ch
Server: Apache/2.0.52 (Unix) PHP/4.3.10 mod_ssl/2.0.52 OpenSSL/0.9.7c-p1

某所
Server: Apache/1.3.26 mod_throttle/3.1.2 mod_ruby/0.9.7 Ruby/1.6.4 mod_python/2.7.8 Python/2.2.1 mod_perl/1.26 DAV/1.0.3 PHP/4.2.3 mod_jk/1.2.0

mod_throttle/3.1.2 で接続制限できるらしい