RSH to Ubuntu machine from Solaris machine?

This is probably really basic compared to what you guys are usually talking about here, but I have a problem and I have no idea what to do about it. I try to RSH to my Ubuntu computer from my Solaris one and run into a dead end:

>> rsh 192.168.1.103
::ffff:192.168.1.103: Connection timed out
>> 

This is within an internal network, not over the internet. And I'm sure that 192.168.1.103 is the correct IP address. I am able to RSH to other computers running Solaris, just not this one Ubuntu one. What should I do?

*** EDIT ***
I almost forgot, I'm able to RSH from Ubuntu to Solaris, but not the other way around. If that matters.

does this help?

also why not use ssh?

Is there a difference? Besides ssh being encrypted. I assume since I'm doing this within my network I won't need to encrypt the anything.

---------- Post updated at 04:24 PM ---------- Previous update was at 03:54 PM ----------

It helped at first, when they said to install rsh-server from the repos. But then when they went on to say they had a problem with it, the final post at the bottom says what needs to be running but doesn't really elaborate on how to do so. I went to the link he posted, and didn't find much help. I also googled the things he suggested and still got nowhere. I'm still getting a 'connection timed out' error even though I installed rsh-server and configured /etc/hosts.equiv and /$HOME/.rhosts with help of the tutorial I found.

is the rshd service running?

and even if it is your internal network you should go for ssh...

rshd is not running. Does that come with the package I just downloaded or is there something else I need to download? rshd is not a package in the repos. OK, I'll use SSH from now on then. But I'm not sure why since there's not really any threat from within my network. But it's not much extra trouble to type an s instead of an r so I might as well.