Delay in SSH connection in Ubuntu Feisty

Fri, 07/20/2007 - 14:33 — Frits Jalvingh

I just grew fed up with all of my ssh connections taking more than 15 seconds before a connection was established. I ruled out the usual suspects:

Misconfigured DNS can cause it as a reverse lookup times out. This however was not the case. dig -x [ipaddress] worked fine on the server.
When ipv6 on the workstation is misconfigured it can cause the problem because ssh will try to connect over ipv6 before connecting thru ipv4. I disabled ipv6 (alias net-pf-10 off in /etc/modprobe.d/aliases) but still no go. I could have guessed since my ipv6 route table was empty..

I fired up wireshark and traced a connection. The cause of the problem was mdns which did lookups that timed out. $DEITY knows why it does; I just disabled it by removing all references to mdns in /etc/nsswitch.conf - and all works fast again

Wireshark is great.

Comments

Thu, 04/28/2011 - 14:13 — Anonymous

Worked great

I commented out the following line (added # in the front)
hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4

and added the following line.
hosts: files dns

my nssswitch.conf file looks like this:
# /etc/nsswitch.conf # # Example configuration of GNU Name Service Switch functionality. # If you have the `glibc-doc-reference' and `info' packages installed, try: # `info libc "Name Service Switch"' for information about this file. passwd: compat group: compat shadow: compat #hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4 hosts: files dns networks: files protocols: db files services: db files ethers: db files rpc: db files netgroup: nis

Thanks for the help!
Joel
----
Ubuntu Desktop 10.10 amd64

Thu, 04/21/2011 - 22:08 — Anonymous

It works!!

Thanks very much for providing this tip - works a treat when creating an ssh connection to my Karmic machine!

Thank you :)

Sat, 03/15/2008 - 04:15 — Anonymous

etc.to

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