Re: [DOC PATCH] Re: tcp_keepalive_intvl vs tcp_keepalive_time?

[Nivedita Singhvi]

> What kind of packets are keepalive packets, by the
> way?  (I don't think the firewall rules are filtering
> them out, but I can't be sure.)

> Rob again. :)

Thanks for correcting the documentation - it was out of date and erroneous.

The keepalive packets are simple tcp segments sent on the connection:

- no data
- ack # is next expected byte
- sequence # is a stale (byte already acked by the other end) one, so that
the
  other end is forced to send an ack in return (as it receives an out of
window
  sequence #).

I cant imagine how a firewall would be filtering them..

thanks,
Nivedita