Home --> IAQ -->

New Connections Pause or Stall

By Jeffrey Howard
All rights reserved unless noted otherwise

Some users of newly installed UNIX systems complain that when they try to connect from another machine, everything seems to pause, stall, or lock-up for a few minutes. Eventually, the connection succeeds and everything works normally.

The cause for this is name lookup. When a machine receives an ftp or telnet connection, often the server will try to look up the name of the connecting machine. If the client machine has no reverse name lookup information, or if the server is has no nameservers configured, that lookup will fail. This server will wait for a generous timeout to expire before giving up, causing the connection to pause for a few moments at the beginning.

One way to handle this is just to ensure that the server has access to a nameserver and that all of the client machines you use can successfully resolve in a reverse lookup. Another option is to short-circuit the lookup process by putting the client computers' names into the /etc/host file with their addresses. Once this is done, the lookups will be near instantaneous, and there should be no perceivable dealy in connecting.