I think I should give you the models of my devices: the router is a wrt54g and the modem is a pk5000. I did a little more searching and read that I can change the firmware on the router but if memory is correct if I screw up it becomes a brick so I need to ask what the benefits are and if there is another way to do it. I just looked closely at the router and it is labled as a wireless router and a 4 port switch. :-)~MIKE~(-: On Sat, Jul 19, 2014 at 11:39 AM, Michael Havens wrote: > >Why were rules written for the second router but not the first? > >Is it because it was connected first? Could we write the rules we need? > > What I meant was the second was connected to the first. > > > :-)~MIKE~(-: > > > On Sat, Jul 19, 2014 at 11:31 AM, Michael Havens wrote: > >> > Going the other way, you have no rules to pass >> > the communication through. >> >> Why were rules written for the second router but not the first? Is it >> because it was connected first? Could we write the rules we need? >> >> >> :-)~MIKE~(-: >> >> >> On Fri, Jul 18, 2014 at 3:34 PM, Gilbert T. Gutierrez, Jr. < >> mailing-lists@phoenixinternet.net> wrote: >> >>> NAT is the reason. The ping is being translated from one network to >>> another as well as telnet. Going the other way, you have no rules to pass >>> the communication through. >>> >>> Gilbert >>> >>> >>> On 7/18/2014 2:44 PM, Michael Havens wrote: >>> >>> so according to your tutorial 192.168.0.x is not on the same subnet as >>> 192.168.1.x. If that is correct why can I ssh (and ping and telnet....) >>> from client to host but not host to client? >>> >>> :-)~MIKE~(-: >>> >>> >>> On Fri, Jul 18, 2014 at 12:30 PM, Michael Havens >>> wrote: >>> >>>> telnet localhost 22 from the server received no answer from the client >>>> telnet 192.168.1.101 22 from the client received no answer from the >>>> server >>>> >>>> I'll get back to you about the research project >>>> (and as a private message) >>>> >>>> :-)~MIKE~(-: >>>> >>>> >>>> On Fri, Jul 18, 2014 at 6:41 AM, wrote: >>>> >>>>> Hello Michael: >>>>> the 'Net' is a hodgepodge of protocols, all abiding to the 'OSI Layer >>>>> Model' to work properly (http://en.wikipedia.org/wiki/OSI_model). >>>>> Troubleshooting your SSH connection should be a fairly simple >>>>> proposition, because there are only so many moving parts (Three!). >>>>> As anything under the OSI model, nothing on an upper layer will work >>>>> unless the necessary components of the lower layer are working. >>>>> AND you *HAVE* to troubleshoot each layer separately. >>>>> So how does this go? >>>>> Well, lets take a look at your SSH problem... >>>>> 1.- In order for the SSH connection to work you need 3 things: >>>>> 1.1.- a SSH server, >>>>> 1.2.- a SSH client and, >>>>> 1.3.- a TCP/IP connection. >>>>> *EACH* one of the lines above is a separate project and *HAS* to be >>>>> addressed as such. >>>>> Lets cover the basics first, the TCP/IP connection: >>>>> You *HAVE* to *KNOW* The Mantra: >>>>> "In order for any 2 devices to establish a TCP connection they have to >>>>> share a physical link and they need addresses in the same subnet". >>>>> The statement above is a pretty dense one, and has several >>>>> implications, number one being: What does "subnet" mean? >>>>> Another is: what about IPs in different subnets? >>>>> We'll get there... >>>>> As there are already several books written (and to be written) about >>>>> the few lines above, I'll water it down to the bare minimum: >>>>> The subnet is defined via the netmask, and implies that "ON" parts of >>>>> the netmask are always equal in all the addresses on a network segment, so: >>>>> Network: >>>>> 192.168.0.0/24 or >>>>> 192.168.0.0 with netmask 255.255.255.0 means that >>>>> *ALL* the addresses in *THIS* network are going to look like >>>>> 192.168.0.${SOMETHING_ELSE} >>>>> '192.168.0' is the "Network", and "${SOMETHING_ELSE}" is the "Host". >>>>> You can not use "Host 0" (because that defines the network) and you >>>>> can not use the highest number (255) because that's the 'broadcast address'. >>>>> Which means that any '/24" (slash 24) network can address 254 'hosts'. >>>>> Network: >>>>> 192.168.0.0/16 or >>>>> 192.168.0.0 with netmask 255.255.0.0 means that >>>>> *ALL* the addresses in *THIS* network are going to look like >>>>> 192.168.${SOMETHING_ELSE}.${SOMETHING_ELSE} >>>>> '192.168' is the "Network", and "${SOMETHING_ELSE}.${SOMETHING_ELSE}" >>>>> is the "Host". >>>>> You can not use "Host 0.0" (because that defines the network) and you >>>>> can not use the highest number (255.255) because that's the 'broadcast >>>>> address'. >>>>> Which means that any '/16" (slash 16) network can address 65534 >>>>> 'hosts'. >>>>> The reason why '255' is the highest number is because IPv4 addresses >>>>> (and netmasks) are represented in memory in 4 bytes, each number one byte. >>>>> Bytes are 8 bits, but that's a different book that you need to read >>>>> too, lets move on with the network. >>>>> Things get pretty interesting (and math pretty convoluted) when you >>>>> define networks like 192.168.127.0/25 >>>>> If yo want to see all variations, you can be lazy (like me) and run: >>>>> ipcalc 192.168.0.127/25 >>>>> Finally, "Netmasks" are a patch to the first defined (and >>>>> shortsighted) 'Address Type' as class A,B,C or D, but I'll let you research >>>>> that yourself. >>>>> >>>>> Well, that's all good, but how do you talk to other addresses?, I talk >>>>> to google.com... >>>>> That's a valid question, but >>>>> 1.- it is not part of *THIS* SSH problem and >>>>> 2.- you don't 'talk to google'. >>>>> We'll talk more about how devices find each other in a network down >>>>> below, but in order to talk to devices outside your network you need the >>>>> 'Routing Protocol' (implemented at [SURPRISE!] 'the router') which is >>>>> nothing else than a table of rules stating 'this IP goes that way'. In >>>>> your case, all addresses go the same place (the router) so the router >>>>> becomes the 'Default Gateway'. As to resolve google, you need the DNS, but >>>>> you knew that... :) >>>>> >>>>> Now that we know what an IP address is, lets move on to the "Physical >>>>> Link". >>>>> Well, a cable will do... >>>>> In the wireless world, the "Association" is the link. >>>>> And how do you validate that? >>>>> iwconfig will tell you what (if anything) you are associated to. No >>>>> association, no link, no connection, no SSH. >>>>> ifconfig will tell you what (if anything) you are wired to. No wire, >>>>> no link, no connection, no SSH. >>>>> Ain't that simple? ;-) >>>>> So we have a link... >>>>> And we have IP addresses in the same subnet. >>>>> So we are connected!!! 8-) >>>>> Not so fast Armando!!! >>>>> The fact that your addresses match is not necessarily a validation, >>>>> because each computer may be connected to a different router providing the >>>>> same NAT(ed) address! >>>>> NAT? >>>>> Yes NAT (Network Address Translation protocol), but that's yet another >>>>> book, so lets water it down: >>>>> NAT is the protocol that allows you to have an 'outside visible >>>>> address' and an 'inside invisible network' in a router. >>>>> NAT (as Netmask) was implemented mainly to alleviate the IPv4 shortage >>>>> address because of the 'class A,B,C or D' mistake, but as a byproduct, you >>>>> can 'hide' behind it, which provides some level of security. How you hide >>>>> is yet another bookshelf and essentially means that you cannot access >>>>> devices 'behind the router' unless the device initiates the connection >>>>> first, and that's how you raise a WEB site from 'behind the router' and why >>>>> you can SSH from 'inside to outside the router' but not the other way >>>>> around, so lets move on... >>>>> So, how do we know that we are connected to the same router? >>>>> Ah, glad you asked: >>>>> ARP! >>>>> Or Address Resolution Protocol. >>>>> *ALL* data transmission is done at OSI layer 2. >>>>> Quick implementation manual: >>>>> OSI layer 1: Cable or association. >>>>> OSI layer 2: MAC address. >>>>> OSI layer 3: IP address. >>>>> Your network doesn't know (and doesn't care) about IP addresses. The >>>>> IP address is there to resolve the MAC address. >>>>> When you say: >>>>> ping 192.168.0.1 >>>>> that generates a 'who has' request from the ARP protocol. >>>>> That request is broadcasted to anyone on the physical link (OSI layer >>>>> 1) >>>>> The device with the IP address interrogated by 'who has' answers with >>>>> its MAC address. >>>>> This IP/MAC address pair is then saved to the ARP table. >>>>> >From there on (and even though the IP address goes along in the >>>>> TCP/IP header) all transmissions are sent to the MAC address. >>>>> But then again, how do you know that your 2 boxes are talking to the >>>>> same router? >>>>> arp -n|grep 192.168.1.1 >>>>> Same MAC? >>>>> Same box. >>>>> Different MAC? >>>>> Same Michael... ;-) >>>>> What do we know so far? >>>>> Well, we know something about line 3 of the very first paragraph. >>>>> What about line 2? >>>>> Type >>>>> which ssh >>>>> You have it or not, and you know what to do, so lets move to line 1. >>>>> We now need to troubleshoot the SSH server. >>>>> Well, that boils down to 2 things, it is working or not... >>>>> You *KNOW* that the SSH server is 'listening' (although not >>>>> necessarily working) when you can connect to the 'port' >>>>> Port? >>>>> Yeah, port... >>>>> Lets move on up in the OSI model to the application layer. >>>>> In order to establish a TCP connection you need an IP connection and a >>>>> port (or a socket and a port) >>>>> The port is to the application what the IP address is to the MAC. >>>>> So if the port is listening, the application is awake. >>>>> And how do we know? >>>>> There are only 975143684 possible ways to validate a 'port is open' >>>>> (or listening) but I am a simple boring guy, so I do: >>>>> telnet localhost 22 >>>>> I either get an answer or not. >>>>> If I get an answer, then we are most likely all good, but if I don't >>>>> get an answer then the ramifications are staggering and I'm not even going >>>>> to think about it. >>>>> In order to check that the other port listens then you: >>>>> telnet ${REMOTE} 22 >>>>> Again, we either get an answer or not. And the 'not' means another >>>>> Sunday drive to the library... >>>>> Finally, why 22? >>>>> Because that's the SSH port and it is defined in the configuration >>>>> file, which you can change to further complicate your (or someone else's) >>>>> life. >>>>> But who and where defined 22 as the SSH port? >>>>> grep -i ssh /etc/services >>>>> And who wrote /etc/services? >>>>> http://www.iana.org/ >>>>> And how do I know all this crap? >>>>> Because I finished LFS!!!! ;-) >>>>> I hope you see everything now as clear as mud. >>>>> Keep this message handy, you'll need to read it several times... >>>>> Keep in mind that what I have written here is a GROSS >>>>> oversimplification of several bookshelves contained in several buildings >>>>> and written along several decades all over the World, it's free advice, you >>>>> can't sue me... :) >>>>> And always remember: >>>>> For every question there exists a simple, direct and wrong answer. >>>>> if you have any question, >>>>> you will get any answer... >>>>> ET >>>>> PS: Research project: >>>>> Why doesn't 'ping' use a port? >>>>> Why is 'ping' 'setuid(ed)' >>>>> What are 'routable' networks? >>>>> What are 'non-routable' networks? >>>>> What does it mean if you get and IP address like 169.254.0.0/16 >>>>> Why do you always have a 127.0.0.1 address in your boxes? >>>>> Who defines (and where are the documents that define) all these >>>>> protocols? (RFC anyone?) >>>>> >>>>> >>>>> Michael Havens writes: >>>>> >>>>>> okay, so I bought a used computer to do Linux from scratch on. Well, >>>>>> I'm >>>>>> going to ssh from my primary computer to the new computer but got a >>>>>> 'Connection timed out' error. After googling for a bit I discovered >>>>>> ufw was >>>>>> to blame. >>>>>> after I disabled the firewall I could ssh from 192.168.1.101 >>>>>> to >>>>>> 192.168.0.4 >>>>>> the error I got going the other way was the connection timed out >>>>>> error: >>>>>> ssh mike@192.168.1.101 >>>>>> ssh: connect to host 192.168.1.101 port 22: Connection timed out >>>>>> After googling some more I thought perhaps openssh-server wasn't >>>>>> installed... but it is. So please.... what is the problem? I verifed >>>>>> openssh-client is installed but I don't know what it could be. Could >>>>>> you >>>>>> help me out? >>>>>> :-)~MIKE~(-: >>>>>> >>>>> --------------------------------------------------- >>>>> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >>>>> To subscribe, unsubscribe, or to change your mail settings: >>>>> http://lists.phxlinux.org/mailman/listinfo/plug-discuss >>>>> >>>> >>>> >>> >>> >>> --------------------------------------------------- >>> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >>> To subscribe, unsubscribe, or to change your mail settings:http://lists.phxlinux.org/mailman/listinfo/plug-discuss >>> >>> >>> >>> --------------------------------------------------- >>> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >>> To subscribe, unsubscribe, or to change your mail settings: >>> http://lists.phxlinux.org/mailman/listinfo/plug-discuss >>> >> >> >