Re: [lwip-users] DHCP end of lease time

[Bob Proulx]

Frédéric Grandjean wrote:
> Do I have to restart my TCP and UDP servers when the address gets changed by 
> DHCP ?

That depends upon the specific daemon.  Off the top of my head I am
aware of these cases.  There are probably more.

1. The daemon listens on the wildcard address.  In this case no
   restarts are needed because connections to the newly changed address
   will match the wildcard okay.  For example:

    tcp    LISTEN     0      128       *:22                    *:*

2. The daemon has bound to a specific address.  In which case yes it
   will need to be restarted (and possibly reconfigured) so that it will
   bind to the new address.  For example:

    tcp    LISTEN     0      80     93.184.216.34:3306                  *:*

3. The daemon polls the list of system devices periodically and
   dynamically adapts to what it finds there.  I seem to recall BIND's
   named being one daemon that does this.  In which case it will
   automatically detect the change and adapt.  For example:

    tcp    LISTEN     0      10     93.184.216.34:53              *:*
    tcp    LISTEN     0      10     127.0.0.1:53                  *:*
    tcp    LISTEN     0      5      192.168.122.1:53              *:*

Bob