[opensuse] ssh access hangs on ipv4, but works fine on ipv6 ?
I have Tumbleweed running on an ARM board - seems to work very well, except ssh access over IPv4. After I type in the password, the client just hangs. Surprisingly, it works fine over IPv6. Does anyone recognise that situation? -- Per Jessen, Zürich (12.7°C) http://www.hostsuisse.com/ - virtual servers, made in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
Per Jessen wrote:
I have Tumbleweed running on an ARM board - seems to work very well, except ssh access over IPv4. After I type in the password, the client just hangs. Surprisingly, it works fine over IPv6. Does anyone recognise that situation?
This appears to be some sort of incompatibity issue - with a somewhat backlevel ssh accessing sshd on Tumbleweed, it only works on IPv6, but hangs on IPv4. Trying the same with ssh from a Tumbleweed machine works on both IPv4 and IPv6. Not sure how to report this. -- Per Jessen, Zürich (10.6°C) http://www.hostsuisse.com/ - virtual servers, made in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 03/24/2017 01:37 AM, Per Jessen wrote:
Per Jessen wrote:
I have Tumbleweed running on an ARM board - seems to work very well, except ssh access over IPv4. After I type in the password, the client just hangs. Surprisingly, it works fine over IPv6. Does anyone recognise that situation? This appears to be some sort of incompatibity issue - with a somewhat backlevel ssh accessing sshd on Tumbleweed, it only works on IPv6, but hangs on IPv4. Trying the same with ssh from a Tumbleweed machine works on both IPv4 and IPv6. Not sure how to report this.
This may be a long-shot, Per, but does failed DNS have anything to do with this? I've seen v4 hangs when DNS wasn't available, there's even a phrase to turn off DNS look-ups in sshd_config. Regards, Lew -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 03/24/2017 03:03 PM, Lew Wolfgang wrote:
On 03/24/2017 01:37 AM, Per Jessen wrote:
Per Jessen wrote:
I have Tumbleweed running on an ARM board - seems to work very well, except ssh access over IPv4. After I type in the password, the client just hangs. Surprisingly, it works fine over IPv6. Does anyone recognise that situation? This appears to be some sort of incompatibity issue - with a somewhat backlevel ssh accessing sshd on Tumbleweed, it only works on IPv6, but hangs on IPv4. Trying the same with ssh from a Tumbleweed machine works on both IPv4 and IPv6. Not sure how to report this.
This may be a long-shot, Per, but does failed DNS have anything to do with this? I've seen v4 hangs when DNS wasn't available, there's even a phrase to turn off DNS look-ups in sshd_config.
Sometimes I've also seen issues with X or agent forwarding. In doubt I would try to disable them explicitly, (ssh -xa ...). You may also try non-interactive login for testing: ssh -4 -xa remotehost true cu, Rudi -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
Rc3bcdiger Meier wrote:
On 03/24/2017 03:03 PM, Lew Wolfgang wrote:
On 03/24/2017 01:37 AM, Per Jessen wrote:
Per Jessen wrote:
I have Tumbleweed running on an ARM board - seems to work very well, except ssh access over IPv4. After I type in the password, the client just hangs. Surprisingly, it works fine over IPv6. Does anyone recognise that situation? This appears to be some sort of incompatibity issue - with a somewhat backlevel ssh accessing sshd on Tumbleweed, it only works on IPv6, but hangs on IPv4. Trying the same with ssh from a Tumbleweed machine works on both IPv4 and IPv6. Not sure how to report this.
This may be a long-shot, Per, but does failed DNS have anything to do with this? I've seen v4 hangs when DNS wasn't available, there's even a phrase to turn off DNS look-ups in sshd_config.
Sometimes I've also seen issues with X or agent forwarding. In doubt I would try to disable them explicitly, (ssh -xa ...). You may also try non-interactive login for testing:
ssh -4 -xa remotehost true
Tnx Rudi - didn't do much good. I'd already tried disabling X forwarding. What I don't understand is - why should any issue _only_ affect IPv4? It's really weird. -- Per Jessen, Zürich (12.8°C) http://www.dns24.ch/ - free dynamic DNS, made in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 03/24/2017 03:59 PM, Per Jessen wrote:
Rc3bcdiger Meier wrote:
On 03/24/2017 03:03 PM, Lew Wolfgang wrote:
On 03/24/2017 01:37 AM, Per Jessen wrote:
Per Jessen wrote:
I have Tumbleweed running on an ARM board - seems to work very well, except ssh access over IPv4. After I type in the password, the client just hangs. Surprisingly, it works fine over IPv6. Does anyone recognise that situation? This appears to be some sort of incompatibity issue - with a somewhat backlevel ssh accessing sshd on Tumbleweed, it only works on IPv6, but hangs on IPv4. Trying the same with ssh from a Tumbleweed machine works on both IPv4 and IPv6. Not sure how to report this.
This may be a long-shot, Per, but does failed DNS have anything to do with this? I've seen v4 hangs when DNS wasn't available, there's even a phrase to turn off DNS look-ups in sshd_config.
Sometimes I've also seen issues with X or agent forwarding. In doubt I would try to disable them explicitly, (ssh -xa ...). You may also try non-interactive login for testing:
ssh -4 -xa remotehost true
Tnx Rudi - didn't do much good. I'd already tried disabling X forwarding. What I don't understand is - why should any issue _only_ affect IPv4? It's really weird.
Could you try to find out that it's really no routing issue, for example forward the traffic via the good client: On the good client do $ socat TCP-LISTEN:1234,fork TCP:server-ipv4-address:22 Then on the broken client: $ ssh -4 good-client -p 1234 You may also try "socat TCP6-LISTEN ..." and "ssh -6 ..." on client, to let the client send ipv6 but the server receives ipv4 via socat. BTW still have not fully understood what is broken exactly, the client or server? ARM or x86? cu, Rudi -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
Rc3bcdiger Meier wrote:
On 03/24/2017 03:59 PM, Per Jessen wrote:
Rc3bcdiger Meier wrote:
On 03/24/2017 03:03 PM, Lew Wolfgang wrote:
On 03/24/2017 01:37 AM, Per Jessen wrote:
Per Jessen wrote:
I have Tumbleweed running on an ARM board - seems to work very well, except ssh access over IPv4. After I type in the password, the client just hangs. Surprisingly, it works fine over IPv6. Does anyone recognise that situation? This appears to be some sort of incompatibity issue - with a somewhat backlevel ssh accessing sshd on Tumbleweed, it only works on IPv6, but hangs on IPv4. Trying the same with ssh from a Tumbleweed machine works on both IPv4 and IPv6. Not sure how to report this.
This may be a long-shot, Per, but does failed DNS have anything to do with this? I've seen v4 hangs when DNS wasn't available, there's even a phrase to turn off DNS look-ups in sshd_config.
Sometimes I've also seen issues with X or agent forwarding. In doubt I would try to disable them explicitly, (ssh -xa ...). You may also try non-interactive login for testing:
ssh -4 -xa remotehost true
Tnx Rudi - didn't do much good. I'd already tried disabling X forwarding. What I don't understand is - why should any issue _only_ affect IPv4? It's really weird.
Could you try to find out that it's really no routing issue, for example forward the traffic via the good client:
On the good client do
$ socat TCP-LISTEN:1234,fork TCP:server-ipv4-address:22
Then on the broken client:
$ ssh -4 good-client -p 1234
You may also try "socat TCP6-LISTEN ..." and "ssh -6 ..." on client, to let the client send ipv6 but the server receives ipv4 via socat.
BTW still have not fully understood what is broken exactly, the client or server? ARM or x86?
I think the server is broken with IPv4 on TW on ARM. I now have two clients, one server. Clients are "office20" and "office64", the server is "nano1". office20/ipv4 -> nano1 - works. office20/ipv6 -> nano1 - works. office64/ipv4 -> nano1 - hangs. office64/ipv6 -> nano1 - works. office64 is my elderly openSUSE 10.3 system, office20 is an openSUSE 13.1, nano1 is running openSUSE TW from a JeOS image. I'll try your suggestion above and report back. -- Per Jessen, Zürich (11.6°C) http://www.hostsuisse.com/ - dedicated server rental in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
Rc3bcdiger Meier wrote:
Could you try to find out that it's really no routing issue, for example forward the traffic via the good client:
On the good client do
$ socat TCP-LISTEN:1234,fork TCP:server-ipv4-address:22
Then on the broken client:
$ ssh -4 good-client -p 1234
Okay, that worked fine. -- Per Jessen, Zürich (11.7°C) http://www.hostsuisse.com/ - virtual servers, made in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 03/24/2017 10:03 AM, Lew Wolfgang wrote:
On 03/24/2017 01:37 AM, Per Jessen wrote:
Per Jessen wrote:
I have Tumbleweed running on an ARM board - seems to work very well, except ssh access over IPv4. After I type in the password, the client just hangs. Surprisingly, it works fine over IPv6. Does anyone recognise that situation? This appears to be some sort of incompatibity issue - with a somewhat backlevel ssh accessing sshd on Tumbleweed, it only works on IPv6, but hangs on IPv4. Trying the same with ssh from a Tumbleweed machine works on both IPv4 and IPv6. Not sure how to report this.
This may be a long-shot, Per, but does failed DNS have anything to do with this? I've seen v4 hangs when DNS wasn't available, there's even a phrase to turn off DNS look-ups in sshd_config.
A simple way to find out is to use the IP address instead of host name. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 03/24/2017 03:21 PM, James Knott wrote:
On 03/24/2017 10:03 AM, Lew Wolfgang wrote:
On 03/24/2017 01:37 AM, Per Jessen wrote:
Per Jessen wrote:
I have Tumbleweed running on an ARM board - seems to work very well, except ssh access over IPv4. After I type in the password, the client just hangs. Surprisingly, it works fine over IPv6. Does anyone recognise that situation? This appears to be some sort of incompatibity issue - with a somewhat backlevel ssh accessing sshd on Tumbleweed, it only works on IPv6, but hangs on IPv4. Trying the same with ssh from a Tumbleweed machine works on both IPv4 and IPv6. Not sure how to report this.
This may be a long-shot, Per, but does failed DNS have anything to do with this? I've seen v4 hangs when DNS wasn't available, there's even a phrase to turn off DNS look-ups in sshd_config.
A simple way to find out is to use the IP address instead of host name.
No, because the server may do reverse (and forward) lookup in both cases. These ones are often the cause of slow connections, etc. sshd_config: UseDNS no and maybe also on client: ssh_config: CheckHostIP no cu, Rudi -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
Lew Wolfgang wrote:
On 03/24/2017 01:37 AM, Per Jessen wrote:
Per Jessen wrote:
I have Tumbleweed running on an ARM board - seems to work very well, except ssh access over IPv4. After I type in the password, the client just hangs. Surprisingly, it works fine over IPv6. Does anyone recognise that situation? This appears to be some sort of incompatibity issue - with a somewhat backlevel ssh accessing sshd on Tumbleweed, it only works on IPv6, but hangs on IPv4. Trying the same with ssh from a Tumbleweed machine works on both IPv4 and IPv6. Not sure how to report this.
This may be a long-shot, Per, but does failed DNS have anything to do with this? I've seen v4 hangs when DNS wasn't available, there's even a phrase to turn off DNS look-ups in sshd_config.
Hi Lew nope, I'm pretty certain it's not DNS related - both the IPv4 and IPv6 addresses are reverse mapped etc., and it's a solid hang, it doesn't timeout. -- Per Jessen, Zürich (13.1°C) http://www.dns24.ch/ - your free DNS host, made in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
participants (4)
-
James Knott -
Lew Wolfgang -
Per Jessen -
Rüdiger Meier