Connect To The Z Over Wlan And Ssh

[rolf]

Hi,

please consider the following situation:

1 Thinkpad X24 laptop with Zonet CF1100 CF wifi card
1 collie zaurus also with a Zonet CF1100 CF wifi card
1 wifi access point not under the control of the user that provides internet connectivity

I want

a) to connect to the Internet both from the Z and the laptop
b) ssh into the Z from the laptop over wifi

The problem is that the AP is set up such that even though both the Z and the computer have a 192.168.1.x IP, they cannot ping each other.

Is there a solution for this?

Rolf

[harvell]

If both the devices have a 192.168.1.x ip address that means they are on the same broadcast domain.  The Wifi Router shouldn't be blocking any icmp (ping) or ssh ports.  What kind of OS is on the PC? Any firewall type software to block ports?

Sorry I just read that you were initiating from the pc to the Z not the Z to the pc.  Can you ping the wifi router?  Are the IP addresses given by DHCP or static? What's the Subnet Mask?

[Meanie]

Hi,

please consider the following situation:

1 Thinkpad X24 laptop with Zonet CF1100 CF wifi card
1 collie zaurus also with a Zonet CF1100 CF wifi card
1 wifi access point not under the control of the user that provides internet connectivity

I want

a) to connect to the Internet both from the Z and the laptop
 ssh into the Z from the laptop over wifi

The problem is that the AP is set up such that even though both the Z and the computer have a 192.168.1.x IP, they cannot ping each other.

Is there a solution for this?

Rolf
[div align=\"right\"][a href=\"index.php?act=findpost&pid=154003\"][{POST_SNAPBACK}][/a][/div]

you will find a lot of info on how to do this if you use google and search for private network configuration and setup. what you are trying to do is generic networking stuff and not much zaurus specific so there is much more resources out there to help you...

[Da_Blitz]

actually this might be a case of the dreaded /proc/sys/net/ipv4/icmp_echo_ignore_all=1

which ignores icmp requests (ie it stealths your box if you have no services enabled) most people have the /proc/sys/net/ipv4/icmp_echo_ignore_broadcast=1 turned on because it helps stop ping storms (ie do ping 192.168.1.255 ona net with about 100 computers repeatdaly and you can use up quite a bit of network capacity, works best on wifi )

just some quickies as i am an avid openwrt tweaker
do you have an ip address on both machines, double check if not run your dhcp client (dhclient <ifname> ol udhcpc -i <ifname>, sets up your nameservers as well (should be the gw address or 192.168.1.1))
check your /etc/resolv.conf, and see if there is a nameserver listed. this is needed for a net connection
check you have a route for the adress class, you need one for the 192.168.1.x adress space and a "default" rule that points to the geatway (192.168.1.1)
/sbin/route does this, ou should have 1 entery per interface that is up + 1 for the gaetway. if these dont exsist then try adding them by hand
/sbin/route add -net 192.168.1.0/24 <ifname>
/sbin/route add default gw 192.168.1.1
keep in mind changing your ip adress and running a dhcp client will clober anything you put in by hand, so if it dosent work automajically then get it set up by hand and then get the others working
you may need to use iwconfig to tell your wifi card wihich hot spot to connect to

thats just off the top off my head. IM me if you need more help, or email me. i prefer to do these things over IM as realtime helps

[grog]

IM me if you need more help, or email me. i prefer to do these things over IM as realtime helps[div align=\"right\"][a href=\"index.php?act=findpost&pid=154015\"][{POST_SNAPBACK}][/a][/div]

Please post the solution back here too. I've got the same problem and was hoping to to skulk for the answer  

[Antikx]

i prefer to do these things over IM as realtime helps
[div align=\"right\"][{POST_SNAPBACK}][/a][/div]

Feel free to use the Zaurus Chat too: [a href=\"http://www.tyrannozaurus.com/?q=chatrooms/chat/1]http://www.tyrannozaurus.com/?q=chatrooms/chat/1[/url]

[rolf]

Hi guys,

thanks for all the answers.  I will try to address the issues you raised.

@harvell:
I am not much of a wifi guru.  My previous experiences on wire LAN match yours of "if they are on the same network, you can ping them".  With the different wifi modes being what they are, I am not certain this is always the case.  

Fact of the matter is, that although both machines are connected to the same AP and have IP .19 and .21 assigned by DHCP with submask of /24, they cannot see each other.  I can ping the wifi-router from both the Z and the X24.   Internet is fine for both, but no ssh from the Thinkpad to the Z.  OS on the PC is edgy.  No firewall.  I can ping the machines just fine at home when the Z is connected over USB on another computer, for example.

you will find a lot of info on how to do this if you use google and search for private network configuration and setup. what you are trying to do is generic networking stuff and not much zaurus specific so there is much more resources out there to help you...
[div align=\"right\"][a href=\"index.php?act=findpost&pid=154010\"][{POST_SNAPBACK}][/a][/div]

Meanie, you are right.  This is not too Z specific.  Nonetheless, "private network configuration setup" on google will not be of much help.  As I said, I don't control the AP and thus the layout of the network.  It seems the wifi AP blocks any connections between the nodes themselves (I assume for security reasons, this AP is semi-public).  I can come up with two options:

a) ad-hoc network between my X24 and the Z -> I lose internet connectivity
b) integrate into the AP network -> seems like I lose direct connection from X24 to Z

I am not sure it is possible for a wifi card to both associate with an AP and a separate ad-hoc network (sort of like interface aliases).  That way I might get what I want.  But neither do I know if this is really feasible nor how to set it up.  Google was no help in this respect and thus I turned here.

actually this might be a case of the dreaded /proc/sys/net/ipv4/icmp_echo_ignore_all=1

Da_Blitz, thank you as well for your answer and your offer of support.  Neither of the machines is configured to block ping requests.  At home I can ping between them fine.  If it was just a ping problem, I could still initiate an ssh connection and be happy.

do you have an ip address on both machines, [...] check your /etc/resolv.conf, [...]
check you have a route for the adress class, you need one for the 192.168.1.x adress space and a "default" rule that points to the geatway (192.168.1.1) [...]
[div align=\"right\"][a href=\"index.php?act=findpost&pid=154015\"][{POST_SNAPBACK}][/a][/div]

I believe the things you mentioned are OK.  I can reach the Internet fine from either machine.  I just cannot connect to another machine (except the gateway AP) on the local (W)LAN.

IM me if you need more help, or email me. i prefer to do these things over IM as realtime helps[div align=\"right\"][a href=\"index.php?act=findpost&pid=154015\"][{POST_SNAPBACK}][/a][/div]

Please post the solution back here too. I've got the same problem and was hoping to to skulk for the answer  :)
[div align=\"right\"][a href=\"index.php?act=findpost&pid=154030\"][{POST_SNAPBACK}][/a][/div]

Sure.  Don't worry.  If we come up with something I will post the resolution here.

Cheers

Rolf

[speculatrix]

you can set up most wifi access points specifically to not let the clients talk to each other; as far as I understand it, when client A talks to client B over wifi when in managed mode, it has to be relayed by wifi access point W

I don't think there's any way round this, it's built into the wireless clients.

The alternative is to put A and B into ad-hoc mode, needing no access point; however you then can't use W to provide internet access.

One hack that might work is to configure A or B as another access point, and be a repeater?

[rolf]

One hack that might work is to configure A or B as another access point, and be a repeater?
[div align=\"right\"][a href=\"index.php?act=findpost&pid=154058\"][{POST_SNAPBACK}][/a][/div]

Good idea.  Do you have any hints on how this could be done?  I guess the repeater would need two wifi cards or an interface alias solution?

[rolf]

you can set up most wifi access points specifically to not let the clients talk to each other; as far as I understand it, when client A talks to client B over wifi when in managed mode, it has to be relayed by wifi access point W

Thanks BTW, for confiming the suspicion I had as a wifi non-geek.

[Da_Blitz]

mmm, seems i broke the chat function on tyrannozaurus, at least at my end

anyway, the wifi card can be in only one mode at a time, so no repeaters
however the idea of using one as a repeater might work but its my understanding that it has some security built in so you cant just be a repeater, you have to do some tricky setup procedure

well there is the final solution, i assume you are doing the road warrior thing and so the Z and the laptop are within reach. so why not do eth over usb with the Z? its ugly and i dont know of many people who like it but it works. you will have to set up routing to work which isnt too hard once you know which flags to flick

[speculatrix]

One hack that might work is to configure A or B as another access point, and be a repeater?
[div align=\"right\"][a href=\"index.php?act=findpost&pid=154058\"][{POST_SNAPBACK}][/a][/div]

Good idea.  Do you have any hints on how this could be done?  I guess the repeater would need two wifi cards or an interface alias solution?
[div align=\"right\"][a href=\"index.php?act=findpost&pid=154064\"][{POST_SNAPBACK}][/a][/div]

if A were a repeater then it would be able to talk to internet via W, and B could talk to internet via A to W, and A would through internal bridge also be able to talk to B and vice versa

[Da_Blitz]

after talking to rolf the main idea is to avoid using the Zs keyboard to do stuff, i suggested bluetooth but thats out (extra hardware) and we cant use usb something about a cable)

i suggested vpn (if you have time) or a reverse ssh by bouncing it off a 3rd host, this seemd to be the best option but was still not ideal (latency sucks when you get 4x trip time for each keypress)

so we tried to get a getty running on the IR port and minicomm in it didnt work, has anyone had any experince in this area? i havent really touched IR before. i only have the theroy but never put it into proctice

[harvell]

@harvell:
I am not much of a wifi guru.  My previous experiences on wire LAN match yours of "if they are on the same network, you can ping them".  With the different wifi modes being what they are, I am not certain this is always the case. 

Fact of the matter is, that although both machines are connected to the same AP and have IP .19 and .21 assigned by DHCP with submask of /24, they cannot see each other.  I can ping the wifi-router from both the Z and the X24.   Internet is fine for both, but no ssh from the Thinkpad to the Z.  OS on the PC is edgy.  No firewall.  I can ping the machines just fine at home when the Z is connected over USB on another computer, for example.

[div align=\"right\"][a href=\"index.php?act=findpost&pid=154055\"][{POST_SNAPBACK}][/a][/div]

Just wanted to make sure the obvious was taken cared of.

[Da_Blitz]

actually its a bloody good system for helping to protect users from each other.

think "virus" and you can see why not being able to connect to others is a good idea on a anon hotspot

still like the reverse ssh option, i can see myself using that one on occasion