openssh and dhcpcd updated today - now sftp cannot find local servers

stevendupuis · 2014-03-20 04:18:27

Hi folks,

I did my update thing this evening 'packer -Syu' and openssh was updated to 6.6p1

[2014-03-19 18:44] [PACMAN] upgraded openssh (6.5p1-2 -> 6.6p1-1)

and dhcpcd was updated to 6.3.2-1

[2014-03-19 18:43] [PACMAN] upgraded dhcpcd (6.3.1-2 -> 6.3.2-1)

and then sftp stopped working as it was ok before the updates.

I get error messages like this:

[dellgx270:steve] /home/steve
1442 20140319 234019 $ sftp laptop.local
ssh: Could not resolve hostname laptop.local: Inappropriate ioctl for device
Couldn't read packet: Connection reset by peer
[dellgx270:steve] /home/steve
1443 20140319 234030 $ _

This is how I network my machines. Its much lighter on resources than either NFS or Samba, but is a bit tricky to configure at first go. The Arch Wiki has some older stuff in it and is a bit confusing for first-time users but I also 'googled' other forums and eventually got things configured correctly. Ubuntu flavors work out of the box, but Arch needs some extra leg-work to get things organized.

I tried removing the ~/.ssh/known_hosts files but that didn't work. Since the error was a resolver issue (according to my error messages) I tried using the IP address of the laptop.local machine 192.168.2.10 and that worked both at the command line and via my file manager thunar (I run XFCE on all my boxes because it works well and with a few additions I can get it to do what I want) ...

Problem is, the IP addresses are assigned by dhcpcd (which means they can get reassigned somewhere else) so I would prefer using the host.local names in scripts and bookmarks etc.

Anyone else having issues of this sort? Inquiring minds need to know!

Regards,
Steve Dupuis

Oracle DBA, Unix and NT Systems Management Services
SGC/EDP Consultants INC. Ottawa, CANADA
mailto:steven.m.dupuis@gmail.com

qinohe · 2014-03-20 11:02:43

Must you run DHCP?, Just my 2 cents, but I would convert to a static address, then add an alias to the hosts file.
This is how I do this, the ssh-server is reachable by IP and local.name.

ukhippo · 2014-03-20 12:13:16

You could always use DHCP reservation to give out static IPs. That's how I've configured my router's DHCP server.

stevendupuis · 2014-03-20 17:33:00

qinohe wrote:

Must you run DHCP?, Just my 2 cents, but I would convert to a static address, then add an alias to the hosts file.
This is how I do this, the ssh-server is reachable by IP and local.name.

I realize that I can use fixed IPs but for me that defeats the purpose of the automation provided by dhcp. There are several devices that connect to my lan - a lot of them are wireless and they come and go. When this is working as it should all I have to do is provide the SSID and the WPA2 password to allow people to use the network and internet. Configuring these devices that come and go with static addresses is time consuming as the devices are not necessarily permanent additions.

Regards,
Steve Dupuis

stevendupuis · 2014-03-20 17:40:03

ukhippo wrote:

You could always use DHCP reservation to give out static IPs. That's how I've configured my router's DHCP server.

Same as reply to qinohe - I have to deal with a server and 5 workstations as well as several laptops, phones and tablets (friends and family).
I was considering downgrading the dhcpcd package to the previous version and testing that. Has anyone else done the downgrade successfully?

Regards,
Steve Dupuis

qinohe · 2014-03-20 18:05:32

stevendupuis wrote:

I realize that I can use fixed IPs but for me that defeats the purpose of the automation provided by dhcp. There are several devices that connect to my lan - a lot of them are wireless and they come and go. When this is working as it should all I have to do is provide the SSID and the WPA2 password to allow people to use the network and internet. Configuring these devices that come and go with static addresses is time consuming as the devices are not necessarily permanent additions.
Regards,
Steve Dupuis

Q: What was acting as DNS server before?, because I can't imagine this being bricked by the dhcpcd upgrade, although I could be wrong ..

WonderWoofy · 2014-03-20 18:14:42

In a situation like this, resolution of hostnames to IP addresses is handled by the dhcp daemon on the router usually. So I don't think your problem has to do with openssh at all. I run OpenWrt with dnsmasq as the dhcp server. I set it to resolve hostnames to IP addresses as well. I use [testing] so it has been a few days, but I think that I had to simply restart dhcpcd after the update to make it properly send the hostname again...

qinohe · 2014-03-20 18:23:59

WonderWoofy wrote:

In a situation like this, resolution of hostnames to IP addresses is handled by the dhcp daemon on the router usually.

This is what I was thinking too, but lots of ISP routers can't handle this task, and only resolve IP addresses.

WonderWoofy · 2014-03-20 18:29:39

@qinohe, I guess there is the possibility that the OP has all local devices listed in every /etc/hosts file, but he/she hasn't specified. I made sure comcast didn't send me one of those crappy router/modem combos, as they are pretty crappy.

qinohe · 2014-03-20 18:35:03

@WonderWoofy, yeah these (mostly cheap) routers you get are nice for two people using it, but not a complete soccer team, then your better off with your own pfsense brick hosting the network

stevendupuis · 2014-03-26 22:29:57

From the Arch Wiki - Networking - Avahi page (this is what I've been using for more than a year):
"Avahi is a free Zero-configuration networking (zeroconf) implementation, including a system for multicast DNS/DNS-SD service discovery. It allows programs to publish and discover services and hosts running on a local network with no specific configuration. For example you can plug into a network and instantly find printers to print to, files to look at and people to talk to. It is licensed under the GNU Lesser General Public License (LGPL)."

I don't use hosts file or anything else to resolve the names of the local workstations and/or devices. I have a relatively new Sagemcom fibre router / modem device, and it has been working well since installation ..

What I've been trying to say - as in my initial post - that this worked properly before I did the dhcpcd update. I'll recheck all the settings for dhcpcd, ssh and sftp (and anything else in my networking configurations) to see if anything is in error. There were no .pacnew files created during that software update. I'll post anything that I learn.

Regards,
Steve Dupuis

stevendupuis · 2014-05-31 23:36:24

** SOLVED **

I eventually found the problem with the avahi - mdns not finding my .local machines.
I went back thru my network configuration a la Arch Wiki and came up with this:

The change I made was to the /etc/nsswitch.conf file

from this:
hosts: files laptop mdns_minimal [NOTFOUND=return] dns

to this:
hosts: files mdns_minimal [NOTFOUND=return] dns laptop

Now ssh, ssh -X and sftp are finding my .local machines via avahi and dhcpcd again.

Hope this helps someone else out.

Regards,
Steve Dupuis

Arch Linux

#1 2014-03-20 04:18:27

openssh and dhcpcd updated today - now sftp cannot find local servers

#2 2014-03-20 11:02:43

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

#3 2014-03-20 12:13:16

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

#4 2014-03-20 17:33:00

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

#5 2014-03-20 17:40:03

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

#6 2014-03-20 18:05:32

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

#7 2014-03-20 18:14:42

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

#8 2014-03-20 18:23:59

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

#9 2014-03-20 18:29:39

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

#10 2014-03-20 18:35:03

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

#11 2014-03-26 22:29:57

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

#12 2014-05-31 23:36:24

Re: openssh and dhcpcd updated today - now sftp cannot find local servers

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