Two different processes sharing a socket?

[jbarelds]

Hi all,

I'm kind of puzzled. I recently started on a new job. From the employers network I cannot use RDP to connect to a server (Win2k3) at home, so I found a service called LogMeIn which enables me to administer my home server from work if needed. LogMeIn works like a charm, but I don't understand how.

LogMeIn consists of a few processes, one of which listens on TCP port 443. The server only has one IP address. As far as I know, only one process can claim a certain socket at a time. But my server is also running a web service using SSL on the default https port (443). Both LogMeIn and the https webservice function properly, both on ipaddr:443(tcp).

I thought maybe LogMeIn somehow manages to have their service to be the first listener at the socket, relaying IP packets with http headers to the web service. But if I nmap my server (from remote) using service detection on the socket, it shows the type and version of the web server. So this is not the case.

Any Win2k3 / Programming / IP guru's here that can explain the above to me?

 

[North323]

its no different that a million people going to yahoo.com over port 80. they are not claiming the 'same' socket but requesting a new socket. port 443 is just that, a port, like a door. SSL is able to serve up more than one socket or connection

 

[jbarelds]

I understand the principle of multiple connections to the same socket, in your example this socket only binds to one process (web server).

This is different then the situation I described, where port 443 on a single IP is used to serve two completely different processes (IIS and LogMeIn).

 

[North323]

the ssl is not the same. the secure socket layer are different. think of port 443 like a door, the ssl is generated by two different parties that use the same 'door' check this out may help:

http://en.wikipedia.org/wiki/Transport_Layer_Security

 

[burtsbees]

one of which listens on TCP port 443.

That IS for SSL logins. The actual service is different.

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!

 

[jbarelds]

Don't really understand what burtsbees is saying, would you please explain?

North323; think I'm starting to understand. I see that a windows service called "httpfilter" handles SSL connections, and this service is not part of IIS, but a standard service. From what you told me, this service can create multiple individual specific SSL sockets for underlying apps that might ask for one. The httpfilter service will claim the specific ip:443 socket. But IIS and the LogMeIn apps interact with the "httpfilter" service in order to get individual SSL sockets.

Please correct me if I've gone horribly wrong somewhere.

If the above is right, then the situation of two completely different apps to use the same socket is an SSL only story, and it's still impossible to do the same for any other non-ssl socket (like running both apache and iis on SpecificIP:80 for example).

 

[stubnski]

What everyone is saying is that you can have multiple applications using port 443 (which is the port that SSL uses - so SSL = 443).

For example: It is like logging into your gmail account and your bank account at the same time, both are using port 443 (SSL) on your computer.

Make sense?

Stubnski

 

[VinceWhirlwind]

er, no, they aren't.

When you log onto your gmail account and your bank account at the same time, each connection from your PC is on a differently-numbered port. Usually the first available port after 1001 is chosen for each new connection.

 

[VinceWhirlwind]

....the other end of your connection is on port 443, of course.
And everybody knows only one person can log onto Gmail at a time. I've been waiting my turn since 2002...

 

[jbarelds]

stubnski,

I don't want to sound offensive in any way, but you don't seem to understand what my post is about. You're confusing a service socket connection with a client connection, as Vince says.

 

[stubnski]

whoops, my mistake. I guess I shouldn't glance through posts before posting.


Stubnski