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Need help with Linux networking interfaces and NIC bonding
by Sean Son 08 Oct '18

08 Oct '18

Hello everyone I am running into some strange issues when configuring networking interfaces on my physical server running Centos 7.5. Let me give you an overview of what's going on: We have a physical server, running CentOS 7.5. This server has one 4 port NIC and one 2 port NIC and a Dell IDRAC port. The first port of the 4 port NIC, em1, is used for Management traffic. The first port of the 2 port NIC, is used for the second port in the NIC bond, device p6p2. The second port on the 4 port NIC, device em2 is the first, port on the NIC bond. These interfaces are using Static IPs. Here is my /etc/sysconfig/network-scripts/ifcfg-em1 file. Please keep in mind that I have changed the IPs and MAC addresses in the files for security reasons: ifcfg-em1: TYPE="Ethernet" PROXY_METHOD="none" BROWSER_ONLY="no" BOOTPROTO="none" DEFROUTE="yes" IPV4_FAILURE_FATAL="no" IPV6INIT="yes" IPV6_AUTOCONF="yes" IPV6_DEFROUTE="yes" IPV6_FAILURE_FATAL="no" IPV6_ADDR_GEN_MODE="stable-privacy" NAME="em1" UUID="bbb2f9c2-141b-4a99-ab1e-328551aae612" DEVICE="em1" ONBOOT="yes" IPADDR="192.168.56.50" PREFIX="24" GATEWAY="192.168.56.1" DNS1="192.168.126.10" DNS2="192.168.220.10" IPV6_PRIVACY="no" NM_CONTROLLED=no as for the ifcfg-bond0 (the configuration file for the NIC bond, which is bond0): DEVICE=bond0 NAME=bond0 TYPE=Bond ONBOOT=yes BOOTPROTO=none IPADDR=192.168.56.70 PREFIX=24 BONDING_MASTER=yes BONDING_OPT="mode=1 miimon=100" TYPE=Ethernet and the ifcfg-slave1 configuration file, which is the first slave port for the NIC bond, this corresponds to em2: DEVICE=em2 HWADDR="c8:2f:87:fg:2a:31" ONBOOT=yes TYPE=Ethernet BOOTPROTO=none MASTER=bond0 SLAVE=yes and the ifcfg-slave2 configuration file , which corresponds to the second slave port for the NIC bond, which is interface p6p2: DEVICE=p6p2 HWADDR="00:6a:d7:7c:e8:09" BOOTPROTO=none ONBOOT=yes TYPE=Ethernet MASTER=bond0 SLAVE=yes I created a custom routing policy for the NIC bond, bond0. Here is the configuration for the routing policy: route-bond0: 192.168.56.0/24 dev bond0 src 192.168.56.70 table t1 default via 192.168.56.1 dev bond0 table t1 and the rule-bond0 file: table t1 from 192.168.56.70 as for the routing table: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.56.1 0.0.0.0 UG 0 0 0 bond0 192.168.56.0 0.0.0.0 255.255.255.0 U 0 0 0 bond0 192.168.56.0 0.0.0.0 255.255.255.0 U 0 0 0 em1 169.254.0.0 0.0.0.0 255.255.0.0 U 1002 0 0 em1 169.254.0.0 0.0.0.0 255.255.0.0 U 1008 0 0 bond0 now here is the scenario I am dealing with: This linux server is used for monitoring purposes. We have Nagios, Cacti and other tools installed on it. There are a few things I have noticed and I want help on: 1) Whenever I ping any of the devices on our network, from this server, the traffic goes out from the management port. I do not want the traffic to go out of the management port. I want it to go out through the active port of the NIC bond. How do I configure the networking so that all primary network traffic flows to and from the NIC bonded interfaces? I only want the management port to be used for SSH purposes and well, management of the server. 2) I have configured the NIC bond in active-backup mode. I notice that when I used another computer to do a continuous ping to the NIC bond, and then I disable one of the slave interfaces of the bond, the ping drops and it does not failover to the backup slave interface and turn into the active one. It also causes any pings to the management port to drop as well. Then when I disable slave2, and enable slave1, the traffic does not fail over to slave1 and the ping continuously fails. It is only when I enable both slave interfaces and then either restart the networking using systemctl restart network, or reboot the server, the networking resumes and the pings succeed again. What steps should I take to fix this issue? Should I even use active-backup mode with the NIC bond or is there a better mode I should use? 3) Ive tested the networking, by changing the VLAN of the NIC bonded ports, on the switch, to a different VLAN, and it caused the management port to stop responding to ping. Why is this and how do I fix that if I decide to one day use two different VLANs for Management and the NIC bond ports? Thank you for all of your help in advance! Sean

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email Server for CentOS 7
by Bee.Lists 08 Oct '18

08 Oct '18

Hi folks. I’m looking for an email server. I have a C7 box already with nginx, PostgreSQL, Sinatra and Ruby. So I don’t want to install PHP, Apache, MySQL, etc. Are there any ways/tutorials to set up a mail server under those restrictions? It would serve multiple domains. Cheers, Bee

11 14

"WARNING: fdisk GPT support is currently new"
by Nicolas Kovacs 07 Oct '18

07 Oct '18

Hi, I'm currently teaching Linux system administration to a class at the local "chambre de commerce". The course is based mainly on a minimal CentOS 7 installation. Usually my preferred tool for handling manual GPT partitioning is gdisk, which is not installed on a minimal install. I just gave the good old fdisk a spin, which enables GPT partition table creation with the 'g' shortcut. Here's what I get when listing a GPT-partitioned drive with fdisk: # fdisk -l /dev/sdb WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion. Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes ... Now my first reaction would be to install gdisk (yum install gdisk) and use this to handle GTP partitioning. But I'm curious. How "experimental" (e. g. prone to blow up in my face) is fdisk really? So far, I've only used it for MBR-style partitioning. Cheers from the sunny South of France, Niki -- Microlinux - Solutions informatiques durables 7, place de l'église - 30730 Montpezat Site : https://www.microlinux.fr Blog : https://blog.microlinux.fr Mail : info(a)microlinux.fr Tél. : 04 66 63 10 32

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CentOS 7.5, Apache 2.4, Kerberos
by rebecca coleman 07 Oct '18

07 Oct '18

Hi List, My goal in sending this email is to get some direction on where to start looking to solve my problem. Thank you all in advance for reading through this and providing any guidance! I'm working on moving to new servers, upgrading from CentOS 6.7 to CentOS 7.5. In this move, we are also upgrading from Apache/2.2.15 to Apache/ 2.4.33. Our servers are all sitting behind a load balancer end point. ====System specifics==== CentOS Linux release 7.5.1804 (Core) Server version: Apache/2.4.33 (Unix) Server built: Jul 3 2018 11:33:42 On all of our CentOS 6.7 machines, kerberos works. On all of our 7.5 machines, it fails. I am looking, at this point, for direction on where to start looking. Here is some relevant information: ====Output from apache error log==== [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of Require all granted: granted [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of <RequireAny>: granted [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of Require all granted: granted [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of <RequireAny>: granted [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of Require valid-user : denied (no authenticated user yet) [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of <RequireAny>: denied (no authenticated user yet) [auth_kerb:debug] src/mod_auth_kerb.c(1643): kerb_authenticate_user entered with user (NULL) and auth_type Kerberos [headers:debug] mod_headers.c(900): AH01503: headers: ap_headers_error_filter() [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of Require valid-user : denied (no authenticated user yet) [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of <RequireAny>: denied (no authenticated user yet) [auth_kerb:debug] src/mod_auth_kerb.c(1643): kerb_authenticate_user entered with user (NULL) and auth_type Kerberos [auth_kerb:debug] src/mod_auth_kerb.c(1400): Verifying client data using KRB5 GSS-API [auth_kerb:debug] src/mod_auth_kerb.c(1416): Client didn't delegate us their credential [auth_kerb:debug] src/mod_auth_kerb.c(1444): Warning: received token seems to be NTLM, which isn't supported by the Kerberos module. Check your IE configuration. [auth_kerb:debug] src/mod_auth_kerb.c(1116): GSS-API major_status:00010000, minor_status:00000000 [auth_kerb:error] gss_accept_sec_context() failed: An unsupported mechanism was requested (, Unknown error) [headers:debug] mod_headers.c(900): AH01503: headers: ap_headers_error_filter() [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of Require all granted: granted, referer: https://six.***********.com/sso [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of <RequireAny>: granted, referer: https://six.***********.com/sso [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of Require all granted: granted, referer: https://six.***********.com/sso [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of <RequireAny>: granted, referer: https://six.***********.com/sso [headers:debug] mod_headers.c(900): AH01503: headers: ap_headers_error_filter() [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of Require all granted: granted, referer: https://six.***********.com/sso [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of <RequireAny>: granted, referer: https://six.***********.com/sso [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of Require all granted: granted, referer: https://six.***********.com/sso [authz_core:debug] mod_authz_core.c(809): AH01626: authorization result of <RequireAny>: granted, referer: https://six.***********.com/sso ====apache vhost files==== ==site specific== <VirtualHost *:80> Define vhost_name siteName Define vhost_home /path/to/site/home Include conf/vhosts.d/template.inc </VirtualHost> ==conf/vhosts.d/template.inc contains== <Directory "${vhost_home}/sso"> AuthType Kerberos AuthName "Kerberos Login" KrbMethodNegotiate on KrbMethodK5Passwd off KrbAuthoritative off KrbAuthRealms [list of realms removed for security] Krb5Keytab "/etc/krb5.keytab" KrbServiceName Any require valid-user ErrorDocument 401 "<html><meta http-equiv=\"refresh\" content=\"0;url=/login/anonlogin.php\"></html>" </Directory> ====And some output from kinit and klist==== $ sudo kinit -V -t /etc/krb5.keytab HTTP/six.***********.com(a)EXT.**********.COM keytab specified, forcing -k Using default cache: /tmp/krb5cc_0 Using principal: HTTP/six.***********.com(a)EXT.**********.COM Using keytab: /etc/krb5.keytab kinit: Client 'HTTP/six.***********.com(a)EXT.**********.COM Kerberos database while getting initial credentials $ sudo klist -etk Keytab name: FILE:/etc/krb5.keytab KVNO Timestamp Principal ---- ------------------- ------------------------------------------------------ 3 09/27/2018 10:22:17 HTTP/one.***********.com(a)aaa.**********.COM (arcfour-hmac) 3 09/27/2018 10:22:17 HTTP/two.***********.com(a)aaa.**********.COM (arcfour-hmac) 3 09/27/2018 10:22:17 HTTP/three.***********.com(a)aaa.**********.COM (arcfour-hmac) 3 09/27/2018 10:22:17 HTTP/four.***********.com(a)aaa.**********.COM (arcfour-hmac) 3 09/27/2018 10:22:17 HTTP/five.***********.com(a)aaa.**********.COM (arcfour-hmac) 3 09/27/2018 10:22:17 HTTP/six.***********.com(a)aaa.**********.COM (arcfour-hmac)

3 2

NetworkManager, multiple IPs, and selinux...
by Sean 07 Oct '18

07 Oct '18

Hello, I was wondering if any one has seen issues with selinux name_bind denials that result from having IP:PORT bindings for services to specific IP addresses managed on an interface under NetworkManager's control? I do realize that people will probably say stop using NetworkManager, and I may, but the behavior is strange, and I'd like to have a better understanding of what's going on. The config is like so: # nmcli c mod eth0 ipv4.addresses 192.168.1.10/24,192.168.1.11/24 # nmcli c down eth0 # nmcli c up eth0 # getenforce Enforcing # systemctl start httpd <errors> permission denied binding to 192.168.1.10:443 Apache has two simple IP based VHosts, site1 and site2, with different (and correct dns records and ssl certs). I'm snipping the config because I know the Apache config works. Listen 443 <VirtualHost 192.168.1.10:443> ... <VirtualHost 192.168.1.11:443> ... I find the denial strange. I've done some testing such as removing one VHost's config and adding a NIC to the VM (eth1) and reconfigure to have 1 IP on each NIC and use both Vhosts. Either way, the selinux denial disappears and everything works. All the packaged selinux policy relating to httpd_t and access to port 443 is correct. I don't doubt that if I ditched NetworkManager and went for eth0:0 and eth0:1 for the IP interfaces, all would be well. I'd just like to see if anyone has some input on the issue. --Sean

3 2

Swap space and hibernation on Centos 7
by H 06 Oct '18

06 Oct '18

I just reinstalled Centos 7 on my Dell Inspiron 15 7570. This time I created a swap partitition that is 24 Gb in size since the machine has 16 Gb of memory. Still unable to hibernate with 'systemctl hibernate' which generates a message that a 'dependency on hibernate.target failed'. Typing swapon -s or cat /proc/swaps I see: /dev/dm-2 partititon 25161724 0 -1 free -m gives me: ... Swap 24571 0 24571 What am I missing? Suggestions what to check are appreciated.

1 0

How to install Banshee on CentOS 7?
by MRob 04 Oct '18

04 Oct '18

on centos 7 I tried to install banshee from EPEL yum install banshee gotting this error: Error: Package: banshee-2.6.2-11.el7.x86_64 (epel) Requires: libgpod-sharp >= 0.8.2 You could try using --skip-broken to work around the problem You could try running: rpm -Va --nofiles --nodigest seems known problem but ignored to fix it in a year or more: https://bugzilla.redhat.com/show_bug.cgi?id=1406012 I tried "yum insall --skip-broken banshee" however this will skip banshee itself! lol what else can I do to install banshee?

2 1

Copy to smb share fails with "invalid argument" on CentOS 7
by Toralf Lund 04 Oct '18

04 Oct '18

Hi, I've had problems copying files to Windows shares from my CentOS 7 machine lately. I originally got this in the desktop file manager, but find that I can also reproduce using gvfs-copy. "cp" to the directory mounted by gvfs works just fine, on the other hand. Also, the problem does not occur with small files - I think anything below 64k is OK. The following command sequence should illustrate the problem (note that some of the names have been changed): [toralf@osl-97214 ~]$ dd if=/dev/zero of=tst.zero bs=65537 count=1 1+0 records in 1+0 records out 65537 bytes (66 kB) copied, 0.000919358 s, 71.3 MB/s [toralf@osl-97214 ~]$ gvfs-copy tst.zero "smb://pgs.com;toralf.lund@ourserver/theshare/" Error copying file tst.zero: Invalid argument [toralf@osl-97214 ~]$ cp tst.zero /run/user/1234/gvfs/smb-share:domain=pgs.com,server=ourserver,share=theshare,user=toralf.lund/ I actually get numerous references to similar issues when I search the web, including https://bugzilla.redhat.com/buglist.cgi?quicksearch=%22invalid%20argument%2… - but they seem to indicate that the cause was a samba issue that was resolved some time in during version 3 release cycle, and I have samba-4.7.1-9. Also, I never actually had problems like this with samba 3. Has anyone else seen this? Is there a way around it? Thanks. - Toralf

1 0

2038 year Problem
by Johann Fock 04 Oct '18

04 Oct '18

Hallo Im using CentOS 7 Ist the 2038 year Problem solved in CentOS 7.5 64 bit Version Thanks Johann Fock Von meinem iPad gesendet

11 15

Trouble installing with Nvidia card
by Elliott Balsley 03 Oct '18

03 Oct '18

Hi all, I'm having trouble doing a fresh install of CentOS 7.3. I'm using the DVD installer ISO, burned to a USB flash drive. The system is a Supermicro 7048 with four Nvidia Titan Xp GPUs, and I have the monitor connected to the first GPU. In the BIOS, VGA priority is set to Offboard, so I am seeing POST messages (good). The CentOS installer begins and shows a few messages on my monitor, but it stops after "Reached target Basic System" ok. At this point, if I connect a second monitor to the motherboard VGA port, then I see the installer continuing on that screen. Is there some way to install without using a VGA monitor? Thanks in advance.

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