This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
Hi Alan, re: > I received you last message. To answer your last question first, I > believe it was early to mid-February when I downloaded McIDAS. I > downloaded it from the web portal at UCAR. OK. I want to use this information to track down the IP address the distribution was downloaded to. However, if your machine was at your UGa office when you did the download, the IP will not do me any good. > Once I brought this machine > home from work and set it up (after getting DSL and the router working), > that's when I tried again to get further with the installation of > McIDAS. Hmm... > The name of the machine is Constellation. That is, my terminal prompts > read: > > [mcidas@Constellation ~]$ > > I looked again at my Linksys router setup. This is the information that > I copied from it: > > IP Address: 72.148.224.143 > Subnet Mask: 255.255.255.255 > Default Gateway: 65.14.248.28 > DNS1: 205.152.37.23 > DNS2: 205.152.144.23 Things now make a lot more sense. I had not realized that you were working your machine at home, or that your machine's connection to the Internet was through a router (LinkSys WRT55AG). My inability to get to your machine (SSH, ping, telnet) is likely due to one of two things: - configuration in your router - configuration in the firewall on your machine (IPTABLES) - your ISP blocking requests destined for your home network In the configuration setup for the LinkSys WRT55AG, under the Security Tab - Firewall is a setting that allows you to Block Anonymous Requests. The WRT55AG Users Guide says that this: "When enabled, this feature keeps your network from being "pinged" or detected by other Internet users. It also reinforces your network security by hiding your network ports. Both functions of this feature make it more difficult for outside users to work their way into your network. This feature is enabled by default. Disable it to allow anonymous Internet requests. This may have something to do with my not being able to ping your machine. Then again, one can turn off pings in the Linux firewall (IPTABLES). > Not yet being as knowledgeable as I'd like to be, I am not sure if the > last two (DNS1 & 2) pertain to the two different computers that are > attached to the router. No, DNS stands for Domain Name Service. The DNS servers listed are machines that machines in your home network use to do name <-> IP translations. > Nonetheless, when on either computer and when I > ping the address finder, the response is 72.148.224.143. Address finder? I am unfamiliar with this term. Can you login to your work machine(s) from home? The reason I ask, is that when I login to Unidata machines from my home machine (which is behind a LinkSys WRT54G router), I can run the 'who' command (I login to Unix machines), and 'who' lists who is logged on AND the machine name/IP address they are coming from. If you login to a UGa machine from home, and the UGa machine runs Unix/Linux, then you too can run 'who' and find out the IP address that your machine has been given by your ISP. This is the IP address I need to login to your machine. NB: even with your IP address, I may not be able to get to your machine if any of the three conditions I listed above are blocking access. > When I type the IP in the browser, it takes me to the router (WRT55AG). > There is no username--it is blank. You only supply the p w, then you > see the router. Right. We know that the IP address of your router is 72.148.224.143. What we do not know is the public IP address of your Linux machine. Your WRT55AG router performs a Network Address Translation (NAT). This converts the IP address it (the WRT55G) assigned to your Linux box (I assume you configured your WRT55AG to run DHCP) into the public address that will be seen on the network. > Again, that is from this machine--I tried from UGa to > get to the machine today, but couldn't--thinking that I was coming from > a different domain than the UCAR range. Perhaps, but I think that your system is not setup to allow SSH access from the outside world. > I think I have things set for the use of Port 22. That is, enabled SSH1 > access and specified port 22. Where? I assume you are talking about the firewall setup on the Linux box; true? > Not sure if this will get us further--let me know if there is something > else to look at or report on. I think that you need to work with someone local (it will be quicker) to setup your home network + Linux machine to allow someone to SSH to it from the Internet. As soon as you can get that working from your UGa machine(s), then your Linux system's firewall can be configured to only allow SSH (port 22) access to machines from the unidata.ucar.edu domain (128.117.140.*) and from your UGa domain (if you want to be able to contact your home machine from work). I think we are almost there... Cheers, Tom **************************************************************************** Unidata User Support UCAR Unidata Program (303) 497-8642 P.O. Box 3000 address@hidden Boulder, CO 80307 ---------------------------------------------------------------------------- Unidata HomePage http://www.unidata.ucar.edu **************************************************************************** Ticket Details =================== Ticket ID: MET-935016 Department: Support McIDAS Priority: Normal Status: Closed