Re: [CentOS] Networking/routing issue

[tdukes]

 Original Message 
Subject: Re: [CentOS] Networking/routing issue
From: Ulf Volmer 
Date: Sat, September 03, 2016 5:47 am
To: centos@centos.org

On 09/03/2016 01:31 PM, TE Dukes wrote:

> Centos 6.8 server eth0 > 192.168.1.110 > gateway 192.168.1.111
> eth1 > 192.168.1.111 > gateway
> 192.168.1.100
> |
> |
> Switch > other computers and devices > gateway 192.168.1.110
> 
> I want to send all internal traffic through 192.168.1.110, all external
> traffic through 192.168.1.111, then back through 192.168.1.110.

As far as i understand, you have two interfaces in the same subnet.

This is usually a bad idea.

best regards
Ulf Volmer

A few of the examples I tried, had them on different subnets. I will
change that and see what happens.

Thanks
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Re: [CentOS] hacking grub to control number of retained kernels.

[Liam O'Toole]

On 2016-09-03, Fred Smith
 wrote:
> I've recently had this problem on two C7 systems, wherein when doing
> "yum update", I get a warning about /boot being low on space.
>
> both systems were installed using the partition size recommended by
> Anaconda, right now "df -h" shows /boot as 494M, with 79M free.
>
> I don't store unrelated crap on /boot, I assume that yum and/or grub
> will manage it for me. So, why, after over a year, is it running low
> on space on two different systems?
>
> Is there some location in /boot where junk piles up, but shouldn't,
> that I have to know about so I can clean it out?
>
> I see EIGHT initramfs files in /boot, two per kernel, same name but
> one has a kdump just before the .img suffix. do I need those for old
> kernels that I may or may not ever boot? (they're 30 to 50 MB each).
>
> For the moment I've edited /etc/grub.conf and changed
> installonly_limit from 4 to 3. (related question: do I need to
> manually remove the oldest kernel, having done this, or will yum/grub
> clean it up the next time there's a kernel to install?)
>
> thanks!
>
> Fred

I recommend the package-cleanup command from the yum-utils package. See
the '--oldkernels' option in particular; it will remove obsolete
kernels, i.e., those which are no longer installable from your yum
repositories.

-- 

Liam

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Re: [CentOS] mounting lvm2

[Steven Tardy]

> On Sep 3, 2016, at 9:22 AM, Alice Wonder  wrote:
> 
> Where do I go from here to mount that volume?

vgdisplay to find the UUID, vgrename takes UUID as a source.
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Re: [CentOS] Networking/routing issue

[Tony Mountifield]

In article <003101d205da$b35b9a20$1a12ce60$@palmettoshopper.com>,
TE Dukes  wrote:
> > Hello,
> > 
> > I've been working on this for over a week. I don't think its working the
> > way it should.
> > 
> > Here's what I'm trying to do:
> > 
> > I have a Windstream dsl router with wireless > 192.168.1.100
> > |
> > |
> > Centos 6.8 server eth0  > 192.168.1.110 > gateway 192.168.1.111
> >  eth1 > 192.168.1.111 > gateway
> > 192.168.1.100
> > |
> > |
> > Switch > other computers and devices > gateway 192.168.1.110
> > 
> > I want to send all internal traffic through 192.168.1.110, all external
> > traffic through 192.168.1.111, then back through 192.168.1.110.
> > 
> [Thomas E Dukes] 
> The above needs a little clarification: all external traffic through
> 192.168.1.111 > 192.168.1.110> all other computers and devices.

Assuming your subnet mask is 255.255.255.0, you have both interfaces on the
same subnet, which won't work. You have two options:

1. Change the third number on the DSL router and on eth1, e.g. 192.168.2.100
   and 192.168.2.111

2. Change the third number on eth0 and all the other computers and devices.

Either of the above options will work. Choose whichever gives you least hassle.

You need to make sure that all of the other devices have the address of your
server's eth0 set as their default gateway. The server needs to have the
address of the router as its default gateway.

If the other devices want to get their addresses via DHCP (a good idea), you
will need to run a DHCP server on your server machine, as they will be isolated
from the router.

You will also need to make sure IP forwarding is enabled on the server.

Cheers
Tony
-- 
Tony Mountifield
Work: t...@softins.co.uk - http://www.softins.co.uk
Play: t...@mountifield.org - http://tony.mountifield.org
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Re: [CentOS] mounting lvm2

[Alice Wonder]

On 09/03/2016 06:33 AM, Ulf Volmer wrote:

On 09/03/2016 03:22 PM, Alice Wonder wrote:


Trying to mount drive on my laptop via USB interface. Which is easy when
drives are plain old ext4 and not ext4 sitting on top lvm2.



[root@localhost ~]# vgs
  VG #PV #LV #SN Attr   VSize   VFree
  centos   1   3   0 wz--n- 111.30g0
  centos   1   3   0 wz--n- 223.08g0


This is the reason why i normally set the VG name to the hostname.

But you can try to rename the VG. Pick the VG UUID from vgdisplay and
rename it:

vgrename $UUID centos-pc

HTH,
Ulf



Thanks, I'm on the right track now.
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Re: [CentOS] mounting lvm2

[Ulf Volmer]

On 09/03/2016 03:22 PM, Alice Wonder wrote:

> Trying to mount drive on my laptop via USB interface. Which is easy when
> drives are plain old ext4 and not ext4 sitting on top lvm2.

> [root@localhost ~]# vgs
>   VG #PV #LV #SN Attr   VSize   VFree
>   centos   1   3   0 wz--n- 111.30g0
>   centos   1   3   0 wz--n- 223.08g0

This is the reason why i normally set the VG name to the hostname.

But you can try to rename the VG. Pick the VG UUID from vgdisplay and
rename it:

vgrename $UUID centos-pc

HTH,
Ulf

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[CentOS] mounting lvm2

[Alice Wonder]

CentOS 7 for everything

I am probably never using lvm again. I have never not once actually 
benefited from its capabilities but this is probably the third or fourth 
time it has gotten in my way.


Issue is that I use the tools so rarely that I can't recall what needs 
to be done to properly mount the drives on another system and finding 
that info on the web is becoming more difficult as the noise in search 
results increases, more and more results are damn youtube videos, and my 
eyes are deteriorating. So its just fixed ext4 for me in the future, KISS.


End of rant. PC mobo died. Most data I need from it backed up to github, 
few things done that day didn't make the last commit and I'd rather not 
do them again.


Trying to mount drive on my laptop via USB interface. Which is easy when 
drives are plain old ext4 and not ext4 sitting on top lvm2.


* end frustrated rant *

[root@localhost ~]# vgs
  VG #PV #LV #SN Attr   VSize   VFree
  centos   1   3   0 wz--n- 111.30g0
  centos   1   3   0 wz--n- 223.08g0
[root@localhost ~]# vgscan
  Reading all physical volumes.  This may take a while...
  Found volume group "centos" using metadata type lvm2
  Found volume group "centos" using metadata type lvm2
[root@localhost ~]#

[root@localhost ~]# pvdisplay /dev/sdb2
  --- Physical volume ---
  PV Name   /dev/sdb2
  VG Name   centos
  PV Size   111.30 GiB / not usable 4.00 MiB
  Allocatable   yes (but full)
  PE Size   4.00 MiB
  Total PE  28492
  Free PE   0
  Allocated PE  28492
  PV UUID   mnFTy9-PoVX-paaA-iBML-kXh5-1Zk5-PQTPW1

[root@localhost ~]#

That's the volume that I need to mount, it is in a VG named centos which 
is the same VG name as what the laptop I am using uses.


I have created /mnt/tmp which is where I want to mount it.

I am a bit worried both having the same VG name (centos) may be an 
issue, I believe the next step is suppose to be to use vgchange to 
activate the volume group but I am a bit hesitant to issuing that 
command with an argument that includes a volume group that is already 
active.


There is only one physical disc in the volume I need to mount, that was 
a lesson I learned the hard way previously - don't use multiple disks in 
a LVM2 volume without hardware redundancy. And with today's disk sizes 
it really isn't needed, not for what I do.


Where do I go from here to mount that volume?

Thanks.



--
-=-
Sent my from my laptop, may not be able to respond timely
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Re: [CentOS] Network manager cannot connet to the Internet

[sunyeping]

Hi, Earl,
Thank you very much for your prompt response.There is no output for "ip route"I 
don't know what is my default gateway and how to check it? And how to check the 
device that I am connecting to?
Best regards.
Yeping--From:Earl
 A Ramirez Time:2016 Sep 3 (Sat) 18:38To:CentOS mailing 
list Subject:Re: [CentOS] Network manager cannot connet to 
the Internet
What is the output of ip route show, can you ping your gateway, first see
if you can ping your default gateway and if you can't you will have to
check the device that your are connecting to.

-- 
Kind Regards
Earl Ramirez
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Re: [CentOS] Networking/routing issue

[Ulf Volmer]

On 09/03/2016 01:31 PM, TE Dukes wrote:

> Centos 6.8 server eth0  > 192.168.1.110 > gateway 192.168.1.111
>  eth1 > 192.168.1.111 > gateway
> 192.168.1.100
> |
> |
> Switch > other computers and devices > gateway 192.168.1.110
> 
> I want to send all internal traffic through 192.168.1.110, all external
> traffic through 192.168.1.111, then back through 192.168.1.110.

As far as i understand, you have two interfaces in the same subnet.

This is usually a bad idea.

best regards
Ulf Volmer

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Re: [CentOS] Networking/routing issue

[TE Dukes]

> -Original Message-
> From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On
> Behalf Of TE Dukes
> Sent: Saturday, September 3, 2016 7:31 AM
> To: 'CentOS mailing list'
> Subject: [CentOS] Networking/routing issue
> 
> Hello,
> 
> I've been working on this for over a week. I don't think its working the
way it
> should.
> 
> Here's what I'm trying to do:
> 
> I have a Windstream dsl router with wireless > 192.168.1.100
> |
> |
> Centos 6.8 server eth0  > 192.168.1.110 > gateway 192.168.1.111
>  eth1 > 192.168.1.111 > gateway
> 192.168.1.100
> |
> |
> Switch > other computers and devices > gateway 192.168.1.110
> 
> I want to send all internal traffic through 192.168.1.110, all external
traffic
> through 192.168.1.111, then back through 192.168.1.110.
> 
[Thomas E Dukes] 
The above needs a little clarification: all external traffic through
192.168.1.111 > 192.168.1.110> all other computers and devices.

> I did an iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE
> 
> Issues:
> 
> Outside connectivity for all other computers and devices only works if
eth0 is
> also connected to the router, server works Iptraf shows no traffic on eth1
> 
> Hope I haven't confused you as I have thoroughly confused myself.
> 
> TIA
> 
> TE Dukes
> 
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[CentOS] Networking/routing issue

[TE Dukes]

Hello,

I've been working on this for over a week. I don't think its working the way
it should.

Here's what I'm trying to do:

I have a Windstream dsl router with wireless > 192.168.1.100
|
|
Centos 6.8 server eth0  > 192.168.1.110 > gateway 192.168.1.111
 eth1 > 192.168.1.111 > gateway
192.168.1.100
|
|
Switch > other computers and devices > gateway 192.168.1.110

I want to send all internal traffic through 192.168.1.110, all external
traffic through 192.168.1.111, then back through 192.168.1.110.

I did an iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE

Issues:

Outside connectivity for all other computers and devices only works if eth0
is also connected to the router, server works
Iptraf shows no traffic on eth1

Hope I haven't confused you as I have thoroughly confused myself.

TIA

TE Dukes

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Re: [CentOS] Network manager cannot connet to the Internet

[Earl A Ramirez]

What is the output of ip route show, can you ping your gateway, first see
if you can ping your default gateway and if you can't you will have to
check the device that your are connecting to.

-- 
Kind Regards
Earl Ramirez
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[CentOS] Network manager cannot connet to the Internet

[sunyeping]

Dear all,
I find out of a sudden my Network manager cannot connect to the Internet. My OS 
is Centos 6.7, and the version of Network manager is Applet 0.8.1. When 
clinking the  Network manager icon at the upper right conner at the Desktop of 
my compuer, I can see in the pop-up manu that there are two network  cards 
(Intel 82573E Gigabit Ethernet Controller (Copper) and Intel 82573L Gigabit 
Ethernet Controller) but only one link (System eth1) available. Usually when 
clicking the "System eth1" the Internet connection would be established. 
However from this morning clicking the "System eth1" only gives connect failure 
information. I don't know whether this is caused by intalling a large software 
package (ambertool 16 ) which requires many updates in my system yesterday.    
But when I give "ifconfig" command in a gnome terminal, the output information 
seems to be correct:

[sunyp@localhost Desktop]$ ifconfig   
eth0  Link encap:Ethernet  HWaddr 00:25:90:72:E2:86  
  UP BROADCAST MULTICAST  MTU:1500  Metric:1
  RX packets:0 errors:0 dropped:0 overruns:0 frame:0
  TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
  collisions:0 txqueuelen:1000 
  RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
  Interrupt:16 Memory:faee-faf0 

eth1  Link encap:Ethernet  HWaddr 00:25:90:72:E2:87  
  inet6 addr: fe80::225:90ff:fe72:e287/64 Scope:Link
  UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
  RX packets:49 errors:0 dropped:0 overruns:0 frame:0
  TX packets:11 errors:0 dropped:0 overruns:0 carrier:0
  collisions:0 txqueuelen:1000 
  RX bytes:16386 (16.0 KiB)  TX bytes:3038 (2.9 KiB)
  Interrupt:17 Memory:fafe-fb00 

loLink encap:Local Loopback  
  inet addr:127.0.0.1  Mask:255.0.0.0
  inet6 addr: ::1/128 Scope:Host
  UP LOOPBACK RUNNING  MTU:65536  Metric:1
  RX packets:90 errors:0 dropped:0 overruns:0 frame:0
  TX packets:90 errors:0 dropped:0 overruns:0 carrier:0
  collisions:0 txqueuelen:0 
  RX bytes:6737 (6.5 KiB)  TX bytes:6737 (6.5 KiB)

What I can do now? Could anyone help me with this problem?
Best regards.
Yeping Sun

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