All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ben Greear <greearb@candelatech.com>
To: netdev <netdev@vger.kernel.org>
Subject: Why is gre0 auto-created, and can we fix it?
Date: Tue, 03 Jan 2012 11:49:50 -0800	[thread overview]
Message-ID: <4F035BDE.5060409@candelatech.com> (raw)

While trying to figure out why 'gre0' doesn't
go away properly in my application, I noticed that
it is auto-created if you just run 'ifconfig gre0'.
(Same thing happens if you use 'ip link show gre0')

As far as I can tell, no other interfaces are auto-created
in this manner.

If I cook up a patch to 'fix' this, would it be acceptable,
or are we stuck with the current behaviour for backwards-compat
reasons?

[root@lec2010-ath9k-1 lanforge]# rmmod ip_gre
[root@lec2010-ath9k-1 lanforge]# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
     link/ether 00:90:0b:13:ed:ea brd ff:ff:ff:ff:ff:ff
3: eth1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
     link/ether 00:90:0b:13:ed:eb brd ff:ff:ff:ff:ff:ff
[root@lec2010-ath9k-1 lanforge]# ifconfig gre0
gre0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-01-00-00-00-00-00-00-00-00-00
           NOARP  MTU:1476  Metric:1

[root@lec2010-ath9k-1 lanforge]# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
     link/ether 00:90:0b:13:ed:ea brd ff:ff:ff:ff:ff:ff
3: eth1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
     link/ether 00:90:0b:13:ed:eb brd ff:ff:ff:ff:ff:ff
76: gre0: <NOARP> mtu 1476 qdisc noop state DOWN
     link/gre 0.0.0.0 brd 0.0.0.0
[root@lec2010-ath9k-1 lanforge]# ifconfig tap0
tap0: error fetching interface information: Device not found

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

             reply	other threads:[~2012-01-03 19:49 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-03 19:49 Ben Greear [this message]
2012-01-03 19:59 ` Why is gre0 auto-created, and can we fix it? David Miller
2012-01-03 20:03   ` Ben Greear
2012-01-03 20:11     ` David Miller
2012-01-21 17:39     ` Krzysztof Halasa
2012-01-21 17:48       ` Ben Greear
2012-01-21 18:40         ` David Miller
2012-01-22 16:48           ` Ben Greear
2012-01-22 19:14             ` David Miller
2012-01-22 19:43               ` Stephen Hemminger
2012-01-22 21:00               ` Ben Greear

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4F035BDE.5060409@candelatech.com \
    --to=greearb@candelatech.com \
    --cc=netdev@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.