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looking for ideas about how to create a constant data stream
by hw＠gc-24.de 30 May '20

30 May '20

Hi, I'm looking for a good way to create a constant data stream that will occupy a bandwidth of about 2--5Mbit/sec between two remote hosts over the internet. I have full access to the hosts involved. My first attempt to use scp to copy data from /dev/null on host A to /dev/null on host B, but scp says '/dev/null: not a regular file'. If something like that would work, I would be able to limit the bandwidth of this transfer in the router(s) involved so that it won't occupy all the bandwidth. Of course, it would be better if I could limit the bandwidth on the sending side rather than dropping packages. I could probably write some program to do that, but since I have never programmed such a kind of network application, it would be rather time consuming. Maybe there's already a kind of tool around that can do this. I need this to work around whatever settings my ISP has made 3 days ago that block my VPN connection so that I effectively can't reasonably work anymore. I do know what the problem with the connection is and that occupying some bandwidth would unblock the VPN; only there doesn't seem to be anything else I could about it.

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Re: [CentOS] Recover from an fsck failure
by James B. Byrne 29 May '20

29 May '20

On Thu, May 28, 2020 19:38, Robert Nichols wrote: > What output do you get from: > > file -s /dev/mapper/vg_voinet01-lv_log > lsblk -f /dev/mapper/vg_voinet01-lv_log > file -s /dev/mapper/vg_voinet01-lv_log /dev/mapper/vg_voinet01-lv_log: symbolic link TO '../DM-5' dm-f lsblk -f /dev/mapper/vg_voinet01-lv_log NAME FSTYPE LABEL UUID MOUNTPOINT vg_voinet01-lv_log (dm-5) The cloned source is a CentOS-6.6 based FreePBSX appliance using lvm. It has a single 500GB HDD. The source host is running and testing of its HDD shows no errors from the test. However, the number of recoverable read and write errors are abnormally high indicating that the HDD is approaching the end of its service life. I wish to replace it without having to rebuild the entire PBX system from scratch. All of the LVMs on the cloned HDD are ext4 file systems. The only one that failed is the log partition /var/log. If I cannot fix this then I wish to replace it with an empty fs and simply rsync the contents of /var/log from the running system to it. I need to do this anyway just prior to replacement as the PBX is running. However, it is about six years since I last had to do this and while I have my notes I would appreciate a short precis of the steps involved. This is the file system layout. /etc/fstab /dev/mapper/vg_voinet01-lv_root / ext4 defaults 1 1 UUID=302ab0fo-f985-4903-86e2-e218b1345e0 /boot ext4 defaults 1 2 /dev/mapper/vg_voinet01-lv_home /home ext4 defaults 1 2 /dev/mapper/vg_voinet01-LogVol04 /var ext4 defaults 1 2 /dev/mapper/vg_voinet01-lv_log /var/log ext4 defaults 1 2 /dev/mapper/vg_voinet01-lv_spool /var/spool ext4 defaults 1 2 /dev/mapper/vg_voinet01-lv_swap swap swap defaults 0 0 tmpfs /dev/shm tmpfs defaults,nodev,. . . parted -l Model: ATA WDC WD1002FAEX-0 (scsi) Disk /dev/sda: 1000GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 1094kB 525MB 524MB primary ext4 boot 2 525MB 500GB 500GB primary lvm Model: Linux device-maper (linear) (dm) Disk: /dev/mapper/vg_voinet01-lv_spool: 68.7GB Sector size (logical/physical): 512B/512B Partition Table: loop Number Start End Size Type File system Flags 1 0.00B 68.7GB 68.7GB primary ext4 Error: /dev/mapper/vg_voinet01-lv_log: unrecognized disk label Model: Linux device-maper (linear) (dm) Disk: /dev/mapper/vg_voinet01-lv_home: 3355MB Sector size (logical/physical): 512B/512B Partition Table: loop Number Start End Size Type File system Flags 1 0.00B 3355MB 3355MB primary ext4 Model: Linux device-maper (linear) (dm) Disk: /dev/mapper/vg_voinet01-LogVol04: 336GB Sector size (logical/physical): 512B/512B Partition Table: loop Number Start End Size Type File system Flags 1 0.00B 336GB 336GB primary ext4 Error: /dev/mapper/vg_voinet01-lv_swap: unrecognized disk label Model: Linux device-maper (linear) (dm) Disk: /dev/mapper/vg_voinet01-lv_spool: 67.1GB Sector size (logical/physical): 512B/512B Partition Table: loop Number Start End Size Type File system Flags 1 0.00B 67.1GB 67.1GB primary ext4 I will have to do this from a live cd I presume as the shell that the failed boot process dropped me into give a "File-based locking initialisation failed." when I try to run vgdisplay or vgs. Any guidance appreciated. -- *** e-Mail is NOT a SECURE channel *** Do NOT transmit sensitive data via e-Mail Do NOT open attachments nor follow links sent by e-Mail James B. Byrne mailto:ByrneJB@Harte-Lyne.ca Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3

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Re: [CentOS] network disconnection after several hours
by Thomas Poty 29 May '20

29 May '20

I will check with firewall-cmd. Regarding hardware problem I have doubt as we use VMWare (but I keep in a corner of my mind).At this moment, we have compiled kernel and have installed it and have tried 4 restore passed.We need to do more tests and understand why 4 restores passed. Thanks Thomas Poty Le jeudi 28 mai 2020 à 23:58:22 UTC+2, hw <hw(a)adminart.net> a écrit : On Tuesday, May 26, 2020 2:42:13 PM CEST Thomas Poty via CentOS wrote: > Hi,We have tried : > - with and without NetworkManager-config-server- with and without > NetworkManagerbut result is still the same : we get disconnection :-/ We > will try with the last kernel. > anybody has a track to explore ? > Thanks > Have you enabled logging with firewall-cmd to see if there are packets being dropped while the dump is being restored? Besides that, one of the first things I'd try is changing out the network card, replace the network cable and use a different port on the switch. Keep in mind that two machines are involved. Even stupid network cables can "switch" between working and non-working for no reason at all like you wouldn't believe ... until you plug them into a PoE switch by mistake after which they suddenly no longer work at all.

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Recover from an fsck failure
by James B. Byrne 28 May '20

28 May '20

This is CentOS-6x. I have cloned the HDD of a CentOS-6 system. I booted a host with that drive and received the following error: checking filesystems /dev/mapper/vg_voinet01-lv_root: clean, 128491/4096000 files, 1554114/16304000 blocks /dev/sda1: clean, 47/120016 files, 80115/512000 blocks /dev/mapper/vg_voinet01-lv_home: clean, 7429/204800 files, 90039/819200 blocks /dev/mapper/vg_voinet01-LogVol04: clean, 770219/20480000 files, 34881086/8102000 blocks fsck.ext4: Bad magic number in super-block while trying to open /dev/mapper/vg_voinet01-lv_log /dev/mapper/vg_voinet01-lv_log The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsk -b 8193 <device> /dev/mapper/vg_voinet-lv_spool: clean, 372/614400 files, 171186/2457600 blocks *** An error occurred during the file system check. *** Dropping you to a shell; the system will reboot *** when you leave the shell. Give root password for maintenance (or type Control-D to continue): I ran mke2fs to locate the backup superblocks: mke2fs -n /dev/mapper/vg_voinet01-lv_log . . . Superblock backups stored on blocks: 32768, 90304, 163840, 229376, 294912, 819200, 884736, 1605632 and ran: e2fsck -b 32768 /dev/mapper/vg_voinet01-lv_log The superblock could not be read or does not describe a correct ext2 The same thing happened for the next backup superblock addrees. And all the rest reported an invalid argument error from e2fsck. Is this recoverable? How? -- *** e-Mail is NOT a SECURE channel *** Do NOT transmit sensitive data via e-Mail Do NOT open attachments nor follow links sent by e-Mail James B. Byrne mailto:ByrneJB@Harte-Lyne.ca Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3

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xinetd custom service - perl - remote address
by Gary Stainburn 28 May '20

28 May '20

Hi all, I can't believe that I can't find the answer to this one. I have a perl script which is called by xinetd. I want that perl script to be able to detect the remote IP address of the caller. I presumed that it would be an environment variable but I could be wrong. I've found reference to the ENV and PASSENV arguments for xinetd.conf but no examples, and no indication of what auguments to use. In my script I have the following code: foreach (keys %ENV) { print "$_=$ENV{$_}\n";} but the only line I get back is: XINETD_LANG=en_US

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Adobe digital editions?
by mark 28 May '20

28 May '20

I had it installed, running under WINE on CentOS 6. Bought a ebook, it insisted it needed ADE, I d/l from the sellers site... setup.exe won't run. Tried d/l 4.5 and 3 from Adobe, neither installer works, The one from their website: file setup.exe setup.exe: PE32 executable (GUI) Intel 80386, for MS Windows, Nullsoft Installer self-extracting archive Anyone run into this yet? I have books I *bought*, and I want them.... mark

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IPv6 inbound routing
by Kenneth Porter 26 May '20

26 May '20

I see my ISP's gateway sending me neighbor solicitations to my external WAN interface for LAN clients on my internal LAN interface. How do I get the box to tell the ISP gateway that my box will route those addresses? I've been assigned a /56 and I'm using a /63 for the DMZ and a /64 for the LAN. The outbound packets seem to reach the destination server but nothing comes back. I'm assuming it's because the ISP router doesn't know to give my box the packets for the LAN clients. I'm using "tcpdump icmp6 -i em2" to watch the exchange. (For outbound routing, I have radvd configured to send router announcements to the LAN, and that seems to work, based on the packets I recieve from the LAN and from watching it with Wireshark on a Win10 client.)

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Re: [CentOS] ip6tables equivalent for NAT?
by John Pierce 26 May '20

26 May '20

with ipv6, you just allow the specific ports destined to the specific local machine(s) in on your WAN side, they don't need translating. same sort of rule as if you had a internet-facing service running on the routing system On Tue, May 26, 2020 at 11:55 AM Kenneth Porter <shiva(a)sewingwitch.com> wrote: > I finally got an ISP connection with working IPv6 and now I need to add > firewall rules for forwarding connections from my LAN to the WAN. I'm > using > firewalld to handle the high-level description that gets translated to > iptables/ip6tables on CentOS 7. > > Of course, with IPv6, one doesn't do NAT, so the usual masquerade target > doesn't make sense. But I want similar connection logic, with no inbound > connections allowed to LAN clients and all outbound connections allowed. > How does one express this in either firewalld or its ip6tables "direct > rules"? > > I don't currently need port-forwarding to internal servers but, for > completeness, what would such rules look like? > > _______________________________________________ > CentOS mailing list > CentOS(a)centos.org > https://lists.centos.org/mailman/listinfo/centos > -- -john r pierce recycling used bits in santa cruz

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ip6tables equivalent for NAT?
by Kenneth Porter 26 May '20

26 May '20

I finally got an ISP connection with working IPv6 and now I need to add firewall rules for forwarding connections from my LAN to the WAN. I'm using firewalld to handle the high-level description that gets translated to iptables/ip6tables on CentOS 7. Of course, with IPv6, one doesn't do NAT, so the usual masquerade target doesn't make sense. But I want similar connection logic, with no inbound connections allowed to LAN clients and all outbound connections allowed. How does one express this in either firewalld or its ip6tables "direct rules"? I don't currently need port-forwarding to internal servers but, for completeness, what would such rules look like?

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network disconnection after several hours
by Thomas Poty 26 May '20

26 May '20

Hello, Here is the context during the problem occurs : We have a new machine running on centos 8.From this machine, we restore a postgresql dump on an other machine runnning on centos 7.After several hoursof running, restore fails due to a disconnection (no route to host).But, if we disable the firewall on centos 8, restore succeed. Before having this new centos 8 machine, we had a centos 7 machine and all worked fine with firewall activated. Has anyboby an ideas, clues or something else? Thanks, Thomas Poty

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