Broadcasts and netmask
by CLOSE Dave
I have a Fedora 20 machine which is receiving UDP broadcast packets at
regular intervals on a high port. No program is presently listening
for these packets. If I run, "tcpdump -iany port 29531", I see each
of the packets arriving just as I expect.
But if I then use Ncat as a surrogate for an application, "nc -lup
29531", I sometimes don't see anything! Why not? (More details
below.) What obvious thing am I missing?
The machine has ten Ethernet ports, two Broadcom BCM5716 and eight
Intel 82576. The Broadcom ports are using the bnx2 driver, the Intel
ports use the igb driver.
Connecting the cable from the broadcast sender to any one of the ports,
I get the exactly same behavior. Without assigning the port an address,
tcpdump shows that the UDP broadcast packets are received but they are
not forwarded to an application. For example,
# ifup eth2
# ifconfig eth2
eth2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet6 fe80::92e2:baff:fe32:f8a8 prefixlen 64 scopeid 0x20<link>
ether 90:e2:ba:32:f8:a8 txqueuelen 1000 (Ethernet)
RX packets 3892 bytes 3552566 (3.3 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 652 bytes 230557 (225.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device memory 0xdc7c0000-dc7dffff
# tcpdump -ieth2 udp port 29531
tcpdump: WARNING: eth2: no IPv4 address assigned
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes
14:40:14.343946 IP 172.17.5.1.60142 > 255.255.255.255.29531: UDP,
length 1212
14:40:15.349595 IP 172.17.5.1.60142 > 255.255.255.255.29531: UDP,
length 1212
14:40:16.360263 IP 172.17.5.1.60142 > 255.255.255.255.29531: UDP,
length 1212
# nc -i2 -lup 29531
Ncat: Idle timeout expired (2000 ms). QUITTING.
(The destination MAC address is FF:FF:FF:FF:FF:FF.)
When I assign the port an address, the result seems to depend on the
netmask I assign. For any netmask from 1 to 19, applications see the
broadcast. For netmasks from 20 through 32, they don't.
# ifconfig eth2 172.17.17.254/19
# nc -i2 -lup 29531
p%�{"00":24,"01":"13/10/15 00:34:36","04":0,"05":0,"06":3,"08":0,...
# ifconfig eth2 172.17.17.254/20
# nc -i2 -lup 29531
Ncat: Idle timeout expired (2000 ms). QUITTING.
For all netmasks, tcpdump still shows the packets being received.
(Obviously, tcpdump doesn't care about the port's address.) But I don't
understand why the drivers treat the broadcast differently based on
the netmask.
Of course, this behavior might not be unique to Fedora but that's the
environment I'm using. If this is known network behavior in general,
I'd sure appreciate some pointer to a reference.
--
Dave Close
9 years, 9 months
unsubscribe
by Ernst Beiglböck
unsubscribe
On Thu, Jul 31, 2014 at 2:00 PM, <users-request(a)lists.fedoraproject.org> wrote:
> Send users mailing list submissions to
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> Today's Topics:
>
> 1. Re: Importing mail archive into Thuderbird (Robert Moskowitz)
> 2. Re: [Bulk] Re: confine user(s) to a core with systemd +
> gcgroup (poma)
> 3. Re: Importing mail archive into Thuderbird (poma)
> 4. Re: Importing mail archive into Thuderbird (poma)
> 5. Re: [Bulk] Re: confine user(s) to a core with systemd +
> gcgroup (Michael Cronenworth)
> 6. Re: Importing mail archive into Thuderbird (joev.8450)
> 7. Re: confine user(s) to a core with systemd + gcgroup (Tim)
> 8. javafx (Mike Wright)
> 9. Re: javafx (Michael Cronenworth)
> 10. Re: abrt questions?? (Cameron Simpson)
> 11. Re: Importing mail archive into Thuderbird (joev.8450)
> 12. lock screen from keyboard in ldxe (Robert Moskowitz)
> 13. Re: OT: ssh and svn+ssh with different keys (Hiisi)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 30 Jul 2014 08:23:37 -0400
> From: Robert Moskowitz <rgm(a)htt-consult.com>
> To: Community support for Fedora users <users(a)lists.fedoraproject.org>
> Subject: Re: Importing mail archive into Thuderbird
> Message-ID: <53D8E3C9.2070405(a)htt-consult.com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
>
> On 07/30/2014 07:21 AM, joev.8450 wrote:
>> did you try the import/export tools extension? available at this link:
>> https://freeshell.de//~kaosmos/mboximport-en.html. btw, it doesn't come
>> up searching for addons. i've used it several times and found it
>> flexible and pretty straightforward.
>
> NO, as I only searched addons. :(
>
>>
>> regards,
>>
>> Joe Verreau
>> Durand, MI
>
> HI, I am over in Oak Park, MI.
>
>>
>> On 07/29/2014 02:58 PM, Robert Moskowitz wrote:
>>> I am asking this here, as my system is F20 with Thunderbird 24.7.0.
>>>
>>> I have downloaded an month's archived messages for Centos-arm and want
>>> to import them into Thunderbird where I could then respond to them more
>>> easily.
>>>
>>> I tried the Tools>Import but when I select email, nothing is listed in
>>> the dialog box. So how might I do the import? Where might i find
>>> instructions?
>>>
>>>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 30 Jul 2014 14:45:54 +0200
> From: poma <pomidorabelisima(a)gmail.com>
> To: Community support for Fedora users <users(a)lists.fedoraproject.org>
> Subject: Re: [Bulk] Re: confine user(s) to a core with systemd +
> gcgroup
> Message-ID: <53D8E902.7000508(a)gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> On 30.07.2014 10:28, lejeczek wrote:
>> hi, thanks for your input, however it does not help really
>> linked doc? I've thumb trough it before.
>>
>> let me rephrase my question - how do I put users, their
>> whole session from the moment they login into a cgroup cpuset?
>>
>> and I don't want to use libcgroup (as it not recommended
>> anyway) but have systemd managed it.
>>
>> thanks
>>
>
> [systemd-devel] Question: who should set up the cpuset cgroup
> http://lists.freedesktop.org/archives/systemd-devel/2013-September/013271...
>
> Check "systemd Development Mailing List"
> http://lists.freedesktop.org/mailman/listinfo/systemd-devel
> for news related to topic, e.g.
> [systemd-devel] confine user(s) to a core with systemd + cgroup
> http://lists.freedesktop.org/archives/systemd-devel/2014-July/021636.html
>
>
> poma
>
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 30 Jul 2014 15:11:43 +0200
> From: poma <pomidorabelisima(a)gmail.com>
> To: Community support for Fedora users <users(a)lists.fedoraproject.org>
> Subject: Re: Importing mail archive into Thuderbird
> Message-ID: <53D8EF0F.7090007(a)gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> On 30.07.2014 13:21, joev.8450 wrote:
>> did you try the import/export tools extension? available at this link:
>> https://freeshell.de//~kaosmos/mboximport-en.html. btw, it doesn't come
>> up searching for addons. i've used it several times and found it
>> flexible and pretty straightforward.
>
> ImportExportTools
> https://addons.mozilla.org/en-US/thunderbird/addon/importexporttools/
>
>
> poma
>
>
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 30 Jul 2014 15:33:03 +0200
> From: poma <pomidorabelisima(a)gmail.com>
> To: Community support for Fedora users <users(a)lists.fedoraproject.org>
> Subject: Re: Importing mail archive into Thuderbird
> Message-ID: <53D8F40F.3080207(a)gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> On 30.07.2014 14:23, Robert Moskowitz wrote:
>>
>> On 07/30/2014 07:21 AM, joev.8450 wrote:
>>> did you try the import/export tools extension? available at this link:
>>> https://freeshell.de//~kaosmos/mboximport-en.html. btw, it doesn't come
>>> up searching for addons. i've used it several times and found it
>>> flexible and pretty straightforward.
>>
>> NO, as I only searched addons. :(
>>
>
> Tools
> -> Add-ons
> -> Get Add-ons(internal browser)
> -> See all
> -> "search for add-ons" <= ImportExportTools
> -> Add to Thunderbird
>
>
> poma
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Wed, 30 Jul 2014 09:21:05 -0500
> From: Michael Cronenworth <mike(a)cchtml.com>
> To: users(a)lists.fedoraproject.org
> Subject: Re: [Bulk] Re: confine user(s) to a core with systemd +
> gcgroup
> Message-ID: <53D8FF51.5090806(a)cchtml.com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
> On 07/30/2014 03:28 AM, lejeczek wrote:
>> hi, thanks for your input, however it does not help really
>> linked doc? I've thumb trough it before.
>
> Correct because systemd doesn't use cpusets.
>
>> let me rephrase my question - how do I put users, their whole session from the
>> moment they login into a cgroup cpuset?
>
> You need to configure a login script (outside of systemd) to do use cpusets.
> Systemd uses CPU accounting and CFS switches to break down resource throttling.
>
>>
>> and I don't want to use libcgroup (as it not recommended anyway) but have
>> systemd managed it.
>
> If you want systemd to manage resources then you're stuck with the existing
> support, which is CPUShares. This will not have CPU limiting the way you desire.
>
> man systemd.resource-control
>
> The newest systemd release has a CPUQuota option that will make this work closer
> to what you want, but if you want true 1-core, 1-process resource limiting
> you're going to have to do it outside of systemd.
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 30 Jul 2014 12:12:30 -0400
> From: "joev.8450" <joev.8450(a)gmail.com>
> To: users(a)lists.fedoraproject.org
> Subject: Re: Importing mail archive into Thuderbird
> Message-ID: <53D9196E.7080301(a)gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> yea, I found it odd that this option was not listed in addon search esp
> when it is discussed in thunderbird support. I have also used the file
> copy approach which worked. Since I was moving from windows ntfs to
> linux fedora I went with the import/export tools extension.
>
> regards,
>
> Joe Verreau
> Durand, MI
>
> On 07/30/2014 08:23 AM, Robert Moskowitz wrote:
>>
>> On 07/30/2014 07:21 AM, joev.8450 wrote:
>>> did you try the import/export tools extension? available at this link:
>>> https://freeshell.de//~kaosmos/mboximport-en.html. btw, it doesn't come
>>> up searching for addons. i've used it several times and found it
>>> flexible and pretty straightforward.
>>
>> NO, as I only searched addons. :(
>>
>>>
>>> regards,
>>>
>>> Joe Verreau
>>> Durand, MI
>>
>> HI, I am over in Oak Park, MI.
>>
>>>
>>> On 07/29/2014 02:58 PM, Robert Moskowitz wrote:
>>>> I am asking this here, as my system is F20 with Thunderbird 24.7.0.
>>>>
>>>> I have downloaded an month's archived messages for Centos-arm and want
>>>> to import them into Thunderbird where I could then respond to them more
>>>> easily.
>>>>
>>>> I tried the Tools>Import but when I select email, nothing is listed in
>>>> the dialog box. So how might I do the import? Where might i find
>>>> instructions?
>>>>
>>>>
>>
>
>
> ------------------------------
>
> Message: 7
> Date: Thu, 31 Jul 2014 02:43:15 +0930
> From: Tim <ignored_mailbox(a)yahoo.com.au>
> To: users(a)lists.fedoraproject.org
> Subject: Re: confine user(s) to a core with systemd + gcgroup
> Message-ID: <1406740395.1293.11.camel(a)paralytic.lan.cameratim.com>
> Content-Type: text/plain; charset="UTF-8"
>
> Just a curiosity question: If you segregate a user to just one CPU
> core, does that really save a system from being crippled if they max out
> that core, or crash it? I'd have thought that the rest of the system
> would still be affected to some degree. At the least, it'd have to be
> completely isolated from the user's core. And it strikes that me that a
> user using the operating system isn't isolated, they interact with it.
>
>
> --
> [tim@localhost ~]$ uname -rsvp
> Linux 3.9.10-100.fc17.x86_64 #1 SMP Sun Jul 14 01:31:27 UTC 2013 x86_64
>
> All mail to my mailbox is automatically deleted, there is no point
> trying to privately email me, I will only read messages posted to the
> public lists.
>
> George Orwell's '1984' was supposed to be a warning against tyranny, not
> a set of instructions for supposedly democratic governments.
>
>
>
>
>
> ------------------------------
>
> Message: 8
> Date: Wed, 30 Jul 2014 11:40:03 -0700
> From: Mike Wright <mike.wright(a)mailinator.com>
> To: Community support for Fedora users <users(a)lists.fedoraproject.org>
> Subject: javafx
> Message-ID: <53D93C03.4060100(a)mailinator.com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
> Hi all,
>
> Does anybody know of any plans to package javafx for fedora? It
> apparently exists somewhere in RedHat.
>
> It provides a top level Window object for containing scenes or pop-ups.
>
> I have an app that won't run without it.
>
> Thanks for any information,
> Mike Wright
>
>
> ------------------------------
>
> Message: 9
> Date: Wed, 30 Jul 2014 14:14:31 -0500
> From: Michael Cronenworth <mike(a)cchtml.com>
> To: users(a)lists.fedoraproject.org
> Subject: Re: javafx
> Message-ID: <53D94417.8060909(a)cchtml.com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
> On 07/30/2014 01:40 PM, Mike Wright wrote:
>> Hi all,
>>
>> Does anybody know of any plans to package javafx for fedora? It apparently
>> exists somewhere in RedHat.
>>
>> It provides a top level Window object for containing scenes or pop-ups.
>>
>> I have an app that won't run without it.
>
> This mail should shed some light on the situation (summary: it's not ready for
> inclusion into Fedora yet):
>
> https://lists.fedoraproject.org/pipermail/java-devel/2013-May/004816.html
>
> You will need to get the Oracle version of Java to use JavaFX for now.
>
>
> ------------------------------
>
> Message: 10
> Date: Thu, 31 Jul 2014 08:42:38 +1000
> From: Cameron Simpson <cs(a)zip.com.au>
> To: Community support for Fedora users <users(a)lists.fedoraproject.org>
> Subject: Re: abrt questions??
> Message-ID: <20140730224238.GA84701(a)cskk.homeip.net>
> Content-Type: text/plain; charset=us-ascii; format=flowed
>
> On 29Jul2014 18:19, bruce <badouglas(a)gmail.com> wrote:
>>hey kevin.
>>Thanks. I'll try, we'll see what the results are!
> [...]
>>On Tue, Jul 29, 2014 at 6:05 PM, Kevin Fenzi <kevin(a)scrye.com> wrote:
>>> On Tue, 29 Jul 2014 14:01:08 -0400
>>> bruce <badouglas(a)gmail.com> wrote:
>>>> Hi Kevin,
>>>> The py app is a test that we created.. I was hopeful that abrt might
>>>> have stored something like, appX crashed at line Y!!
>>>
>>> Just edit:
>>> /etc/abrt/abrt-action-save-package-data.conf
> [...]
>
> Hi bruce,
>
> Just a tangent to this abrt stuff; you _do_ save the stderr of your python apps
> to log files don't you?
>
> If the app aborts because of a regular python exception then there will be a
> nice stack trace in the stderr log file. Simple and direct.
>
> Cheers,
> Cameron Simpson <cs(a)zip.com.au>
>
>
> ------------------------------
>
> Message: 11
> Date: Wed, 30 Jul 2014 20:09:00 -0400
> From: "joev.8450" <joev.8450(a)gmail.com>
> To: Community support for Fedora users <users(a)lists.fedoraproject.org>
> Subject: Re: Importing mail archive into Thuderbird
> Message-ID: <53D9891C.8080103(a)gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Robert,
> how ironic! In fact we used to live just south of eight mile between
> woodward and livernois but that was many years ago.
>
> regards,
>
> Joe Verreau
> Durand, MI
>
> On 07/30/2014 08:23 AM, Robert Moskowitz wrote:
>>
>> On 07/30/2014 07:21 AM, joev.8450 wrote:
>>> did you try the import/export tools extension? available at this link:
>>> https://freeshell.de//~kaosmos/mboximport-en.html. btw, it doesn't come
>>> up searching for addons. i've used it several times and found it
>>> flexible and pretty straightforward.
>>
>> NO, as I only searched addons. :(
>>
>>>
>>> regards,
>>>
>>> Joe Verreau
>>> Durand, MI
>>
>> HI, I am over in Oak Park, MI.
>>
>>>
>>> On 07/29/2014 02:58 PM, Robert Moskowitz wrote:
>>>> I am asking this here, as my system is F20 with Thunderbird 24.7.0.
>>>>
>>>> I have downloaded an month's archived messages for Centos-arm and want
>>>> to import them into Thunderbird where I could then respond to them more
>>>> easily.
>>>>
>>>> I tried the Tools>Import but when I select email, nothing is listed in
>>>> the dialog box. So how might I do the import? Where might i find
>>>> instructions?
>>>>
>>>>
>>
>
>
> ------------------------------
>
> Message: 12
> Date: Wed, 30 Jul 2014 20:26:35 -0400
> From: Robert Moskowitz <rgm(a)htt-consult.com>
> To: users(a)lists.fedoraproject.org
> Subject: lock screen from keyboard in ldxe
> Message-ID: <53D98D3B.1040209(a)htt-consult.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> System is f19 remix on armv7 (Allwinner A20).
>
> The <windows key + l> which is what I use in F20 on x86 with Gnome.
>
> So does ldxe use a different lock screen keystroke, or is something else
> going on here.
>
>
>
>
> ------------------------------
>
> Message: 13
> Date: Thu, 31 Jul 2014 15:43:53 +0400
> From: Hiisi <hiisi(a)fedoraproject.org>
> To: Community support for Fedora users <users(a)lists.fedoraproject.org>
> Subject: Re: OT: ssh and svn+ssh with different keys
> Message-ID:
> <CAPZcXwYgGZRzMcWVDZA7z89VtGZq6LygO0MYVTOCRZiDk8v08Q(a)mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> On 28 July 2014 20:54, Rick Stevens <ricks(a)alldigital.com> wrote:
>
>> "ssh -i <identity file name>" allows you to use a different identity
>> than the default ~/.ssh/id_[d|r]sa" file.
>> ----------------------------------------------------------------------
>>
>
>
> Solved. The problem was that ssh-copy-id didn't copied rsa.pub. Pasted it
> manually to .ssh/authorized_keys on server side. Now everything works like
> a charm.
> Thanks for attention!
> --
> Hiisi.
> Registered Linux User #487982. Be counted at: https://linuxcounter.net/
> --
> Spandex is a privilege, not a right.
>
9 years, 9 months
mount permanently USB Hard Disk
by Angelo Moreschini
Hi,
I have problem to permantly install a USB memory on my computer.
1. ==============
the result of the command ls /dev/sdd* releve the USB Hard Disk in this way:
brw-rw----. 1 root disk 8, 48 Aug 1 14:44 /dev/sdd
brw-rw----. 1 root disk 8, 49 Aug 1 14:44 /dev/sdd1
brw-rw----. 1 root disk 8, 50 Aug 1 14:44 /dev/sdd2
brw-rw----. 1 root disk 8, 53 Aug 1 14:44 /dev/sdd5
2. ==============
the result of the command blkid is this:
.........
/dev/mapper/fedora_zorro-home: UUID="fbff88ad-4e0e-4de4-b370-df5992a8ecbe"
TYPE="ext4"
/dev/sdd1: LABEL="FEDORA" UUID="4458827258826312" TYPE="ntfs"
PARTUUID="39886053-01"
/dev/sdd5: LABEL="REPOSITORIES_subversion" UUID="F6808D39808D00FB"
TYPE="ntfs" PARTUUID="39886053-05"
/dev/sde1: UUID="6CF4-C3AA" TYPE="vfat" PARTUUID="da752cd9-01"
3. ==============
in this way I modified the file /ectc/fstab of my computerin this way :
#
# /etc/fstab
# Created by anaconda on Thu Jun 19 17:41:33 2014
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/fedora_zorro/root / ext4 defaults 1 1
UUID=c3a4694f-d933-4079-a0e8-863320229f64 /boot ext4 defaults
1 2
/dev/mapper/fedora_zorro-home /home ext4 defaults
1 2
/dev/mapper/fedora_zorro-swap swap swap defaults
0 0
#UUID=4458827258826312 /mnt/fedora ntfs default
0 2
#UUID=F68D8D39808D00FB /mnt/svn-repo ntfs default
0 2
==================
but ......
==================
but when I remove the comment from the last two lines of the content of the
file /etc/fstab then the computer start only in EMERGENCY MODE..
I should like appreciate to know what is wrong in the last two line that I
added to the file /ect/fstab..
and also to know I have to change them to have a correct working of the
computer
thank you
regards
Angelo
9 years, 9 months
RoR, apache, passenger deployment problems
by Pete Stieber
I'm trying to deploy a sample ruby on rails application on Fedora 20.
The application runs locally using WEBrick. I have the
mod_passenger-4.0.18-4.fc20.x86_64 package and the associated ruby gems
installed. I'm very new to this so I'm sure I'll be asking some stupid
questions.
The first thing I notice is complaints in /var/log/httpd/error_log when
restarting apache with passenger setup. I've attached the relevant
error_log content. I googled, but couldn't find a clear answer.
Can someone help me out?
Pete
9 years, 9 months