Re: [Slightly OT] Port forwarding (Was: How to restart the root serverfrom within modperl?)

[gr...@mail.netio.org]

When moving a server from MN to VA I used port forwarding to make the
transition totally seamless. This includes DNS.

I wanted to make sure all my services worked in both places, and I didn't
want to have split systems. That would have been a nightmare for services
like e-mail where a message to one server and the user getting mail from
the other server would have been possible.

I used xinetd and it's built in port forwarding capabilities to migrate
one service at a time from MN to VA. Once the service was running in VA,
I'd disable the service on the MN server and forward all traffic to VA.
Went through each service (email, pop, imap, http, etc. etc. etc.) that I
had active this way. Finally, the only thing running in MN was xinetd on
all my active service ports.

Worked beautifully. Users never knew about the server relocation and
absolutely no disruption to services or missed/interrupted mail. Just the
way I like things.

Greg


On Wed, 13 Aug 2003, Craig Edwards wrote:

> Hi,
> I once saw an example of port forwarding using netcat and inetd, i think it involved setting up a listening netcat as the application, using inetd to bind it to a specific port and then forwarding the connection onwards to the ip and/or port where you want it to go, something like this:
>
> service geofwd
> {
>    flags = REUSE
>    socket_type = stream
>    wait = no
>    user = root
>    server = /usr/bin/nc
>    server_args = 192.168.124.38 1005
>    log_on_failure += USERID
> }
>
>
> not sure if this is what you want :-)
>
> Craig
>
> >Hello,
> >
> >ML>If you absolutely need to be in port 80, either setup a simple
> >ML>lightweight apache on port 80 as a reverse proxy (see the mod_perl
> >ML>guide) or, even simpler, do some port forwarding from port 80 to your
> >ML>high port of choice.
> >
> >Has anybody had very good experiences using a simple port forwarder in a
> >production setup? We had a somewhat bad experience with using portfwd
> >under Solaris (images and other binary data got randomly corrupted, and we
> >never got around to figuring out why), and I'm wondering what others use
> >instead. It seems like the port forwarder involved would also be important
> >performance wise.
> >
> >The applications I am typically interested in are forwarding ports on the
> >same interface (like the port 80 example here) as well as between
> >interfaces (or between external interfaces and loopback).
> >
> >Humbly,
> >
> >Andrew
> >
> >----------------------------------------------------------------------
> >Andrew Ho               http://www.tellme.com/       andrew@tellme.com
> >Engineer                    1-800-555-TELL          Voice 650-930-9062
> >Tellme Networks, Inc.                                 Fax 650-930-9101
> >----------------------------------------------------------------------
>
>