File transfers between me and a specific friend are very poor. I can send files to everyone else at a decent speed, but for some reason to this particular user it's as slow as dialup, even though we are both on broadband and if I send the same file by email its very fast.
What could be the cause of this? neither of us is using a firewal, however I have a hardware firewall built into my router.

Thanks.

It's probably due to the router.

If you both use routers and they don't support port forwarding / UPnP then Messenger will use its P2P rather than MSNFTP (I think these are the wrong names, btw).

Basically, P2P is the older file transfer method which sends the file to the MSN Switch-Board server, meaning that your file has to go You - MSN - Friend. MSNFTP creates a direct connection between You and Friend, cutting out the MSN bottleneck - resulting in much improved speeds.

The downside to this is that MSNFTP can only create a connection between external IPs - and if the external IP doesn't resolve directly to the computer which is sending/receiving the file then it can't create the connection.

I can't think of a way to solve this because I believe that the protocol just uses a random un-open port on either computer, meaning that you can't set up manual port forwarding.

Edit: You could put one of your computers in the routers DMZ, however this would mean that any other computers on the network would be unable to listen (ie, create games, run web services, etc.) to the internet. (Although if you've not run into this problem before then it probably won't matter).

slow reply but
my router does support port forwarding and udpn... i can see msn appearing along with several other items in the udnp list. (5110 udp and 64482 tcp)
Its a vigor draytek 2600 vg..
i  still have been unable to find out why my transfers are slow though.

what ports should i even be forwarding?

6891 TCP

what new device? it did detect msn with udnp if thats what u mean? like i said i saw it on the list.