[Standards] binding to tcp for s2s communication

Dave Cridland dave at cridland.net
Sat Mar 8 11:40:40 UTC 2008

On Fri Mar  7 23:41:13 2008, Max Indelicato wrote:
> Along these same lines, there seems to be no way to have multiple  
> xmpp
> servers on one machine. Since we don't know what port the return  
> inbound
> TCP connection will be on, we can't associate it with the initial
> outbound TCP connection unless we do so by IP which essentially  
> makes
> multiple xmpp servers on one system impossible, no?


SRV records allow to independent XMPP services to run on the same IP  
address, by specifying the port to use. Although almost every XMPP  
s2s service operates on port 5269, and most operate on a host named  
by the domain, this isn't actually required.

So although connecting to jabber.org:5269 will give you the  
jabber.org XMPP s2s service, you're meant to find the host and port  
to connect to via a SRV lookup of _xmpp-server._tcp.jabber.org, which  
will tell you what to connect to. There's similar stuff for clients,  

And since XMPP clients (whether s2s clients or c2s clients) say which  
service they require in the stream header itself, you can run  
multiple domains off the same port (typically within the same  
server). Most people do it this way, in fact.

So in fact, yes, you can have multiple XMPP services and servers  
running on the same physical host.

Dave Cridland - mailto:dave at cridland.net - xmpp:dwd at jabber.org
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