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woody1950

join:2007-01-19
Decatur, GA
reply to pablo

Re: SSH connection puzzle

Very bizarre. Yesterday, I rebooted my router (which is running Tomato). After that, I tested from 4 different devices behind the router:
1. Win7 PC. Previously could not connect from this machine, now I can
2. Linux device running Dropbear client: Could not connect before or after
3. Linux device running OpenSSH client: was able to connect before, but now can't.
4. Android phone: Can consistently connect from this device
5. Remote Linux server (not behind this router): Can consistently connect from this device

At this point, I'm really stumped to figure out why these connections are so variable. I'm thinking that it's some kind of routing issue, but I can't figure out where the connection is being blocked. I don't know if rebooting my router was a coincidence, or if I maybe got a new dynamic IP address from my ISP and if that made a difference.


pablo
MVM
join:2003-06-23
kudos:1

Hi woody1950 See Profile,

How about a simple network topology (draw it in ASCII) of your set up. Once we have the topology, we should be able to start simplifying to identify the root-cause.

Cheers,
-pablo
--
openSUSE 12.2/KDE 4.x
ISP: TekSavvy Bonded DSL; backhauled via a 6KM wireless link
Assorted goodies: »pablo.blog.blueoakdb.com


woody1950

join:2007-01-19
Decatur, GA

1 edit



                             ISP(AT&T)
                                 |
                           |DSL Modem|
                                 |
                |Tomato Router/Linux Opware|
                                 |
         --------------------------------------------
        |                        |                   |
   |Win 7 PC|           |Linux server|     |Android Phone|
 

I have Telnet and SSH clients on all of these devices, including the Tomato router.

As I said in my last post, previously, the Win7 PC and the Tomato router were not able to connect, but the Linux Server and the Android phone could. Now, the Win7 PC and Android phone can connect, but the Tomato router and the Linux server cannot connect. In the cases where the devices can connect, I'm able to successfully connect using Telnet as well as SSH. In the cases where I can't connect, both Telnet and SSH fail.

pablo
MVM
join:2003-06-23
kudos:1

Hi,

Please use the "code" tags to format your post.

Thx!
-pablo


woody1950

join:2007-01-19
Decatur, GA

OK, I fixed the post using block code tags. Thanks for the tip!


pablo
MVM
join:2003-06-23
kudos:1

Hi,

Where's the Mac Server in the above scheme? I don't see it in the schematic. Is it on the Internet? Does it have tcpdump on it?

Does your Tomato router have tcpdump?

We'll use the currently failing box, the Linux server for our testing. Let me know on the above.

Thx!
-pablo
--
openSUSE 12.2/KDE 4.x
ISP: TekSavvy Bonded DSL; backhauled via a 6KM wireless link
Assorted goodies: »pablo.blog.blueoakdb.com



koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23

1 edit

tcpdump is available for Tomato-based routers. The easiest way to get a working tcpdump binary is to use a statically-linked version. For most routers (MIPSR1 or MIPSR2-based) you can use this binary:

»multics.minidns.net/tomato/PRECO···/tcpdump

That comes from rhester72's utilities site where he makes some of these things available to folks. I personally prefer to use Entware, but for a quick-and-dirty "I don't have time or the space to deal with Entware I just need tcpdump!" situaiton, the above works.

telnet/ssh into the router, wget the above URL, chmod 755 the binary, go to town. I'm not going to provide a "how to use tcpdump" write-up. Note: this binary does not do IPv6.

P.S. -- I wouldn't be surprised if this turns out to be an IPv6 thing. :P
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.