Questions tagged [checksum]

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Windows Equivalent to `sha256sum -c` (cryptographic hash, digest file, recursive integrity check, SHA256SUMS)

What is the equivalent to sha256sum -c in Windows? I have a set of very important files that I need to copy-to and mirror across many different types of disks in many geographically distinct locations....
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1 answer
153 views

Novice btrfs user: checksum failures and input/output errors galore

A housemate suggested to me that I ought to use btrfs instead of what I've been doing up until now, which is using mdadm with cloned drives, and adding an extra drive into the array to "clone&...
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1 vote
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RPM --queryformat FILEMD5S checksum is different than md5sum of machine

The RPM man page says: The FILEMD5S Tag The FILEMD5S tag is used to display the MD5 checksum for each of the files that comprise the package. Array: Yes (Size: One entry per filemd5s) Used with ...
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TCP checksum errors between linux apps and NICs

I'm writing an internet application and I'm at the stage of crafting my own TCP packets. Except there is a major problem. According to the TCPDUMP utility in linux, every tcp packet that I send out ...
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tcpdump: invalid cksum from client to localhost interface even after disabling offloading

I'm having a strange issue. In linux I have two windows open. one running tcpdump and one running curl. I used curl to try to make a connection to local host and tcpdump logs invalid checksum errors. ...
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2 votes
0 answers
117 views

Disable or recalculate tcp checksum validation on `docker0` interface

Because I need to use esp in transport layer in a docker container, I want to disable tcp checksum verification in the docker container. Is there any way this is possible? If not, is there some way I ...
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1 vote
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OSSEC Multiple "Integrity Checksum Changed" Alerts

I know this question has been asked several times, but the answers do not seem to work. After installing OSSEC server on my Ubuntu Server 18.04 LTS machine, I've received hundreds of "Integrity ...
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2 votes
1 answer
3k views

gpg: no valid OpenPGP data found [closed]

I am trying to make sense of the following two serverfault posts: How to verify a file using an asc signature file? and gpg --import bind-9.9.4.tar.gz.sha1.asc fails with no valid OpenPGP data ...
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Why does Linux' cksum command return the path

When running cksum on a file, let's say /tmp/foo.bar, the linux command returns three values: the checksum, the number of bytes in the file, and the path of the file. Question: Why is the path of the ...
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1 answer
3k views

How to verify checksum after copying 2 TB of 6 million files over USB?

I have a situation where I need to move over 2 TB of data from one server to another server in another data center. There are over 6 million files to copy. The plan is to move data in phases. For ...
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3 votes
1 answer
148 views

Does ZFS, using default settings, use more physical space than ext4 for the same amount of data?

I'm currently considering a switch from ext4 to ZFS and am having trouble finding information about whether or not it uses more or less space to store the same amount of data as ext4. My understanding ...
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2 votes
2 answers
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Why isn't TCP corruption more noticeable?

First of all, apologies if this seems a somewhat simplistic question. According to this answer, TCP packets are corrupted all the time without the checksum catching it. If this happens so often, ...
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32 votes
2 answers
45k views

How to verify a file using an asc signature file?

As an example, this project offers an *.asc file with a PGP signature to verify the contents of the download (as opposed to a checksum, you can see the empty column): https://ossec.github.io/downloads....
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1 answer
584 views

MySQL Table Checksum - Before or after MySQL dump?

The company I'm currently working for has a script that runs at night that takes a MySQL dump of the production environment and imports it into the staging environment. This is a very basic setup - No ...
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recurring, queryable, cached checksumming of all files in a filesystem

I'm looking for a way to efficiently manage and leverage file-level checksums for all files in a filesystem over time. Goals: Configurable, fast refresh - only re-checksumming large files when ...
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1 vote
0 answers
428 views

Suddenly cannot ssh into any machine

Suddenly I was not able to ssh to any machine. I thought it to be my router/network issue & I tried it with different network but the result was same. I took tcp dump on both server & client ...
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1 vote
1 answer
473 views

ICMP/Internet checksum if packet entirely constists of zeros

We are currently investigating a strange behavior of different devices: if we send "empty" ICMP packets (that is, ICMP-SEQ and ICMP-ID are 0x0000 and no ICMP payload), for example using nping --icmp ...
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8 votes
1 answer
2k views

ZFS vdevs accumulate checksum errors, but individual disks do not

I'm running a vendor-specific derivative of FreeNAS 9.3. My trouble started when I installed a new JBOD chassis to add two new vdevs into my pool, and the chassis had a bad board. During this time, I ...
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3 votes
0 answers
1k views

btrfs, Force bad checksum recalculation

A large, USB-connected HDD with btrfs contains a 1TB file (a disk image). The first btrfs scrub after writing that file found 3 logical bad blocks developed somewhere in the middle of that file: [ ...
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How can I replicate Microsoft .NET manifest hashes, ideally on Linux command line?

I have a .NET click-once application which, I found out the hard way (user could not install), checks the checksums of its configuration files against checksums in the .exe.manifest as calculated at ...
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tars with equal content have different checksums

Given are two directories a/ and b/ with apparently equal content, $ diff -Naur a b $ After packing the contents of contents of the directories in to tars, cd a/ && tar cf ../a.tar * &&...
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3 votes
0 answers
543 views

Get checksums of all packages on a yum repo server

I have a server I'm using as a yum reposerver. I've mirrored all the packages I want, and added additional packages in different folders. I've created multiple repos with the createrepo command. There ...
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3 votes
1 answer
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Why am I getting different SHA-1 checksums for tar of identical mongodump backups?

I am trying to backup my MongoDB database and check for changes with a SHA-1 checksum. The problem is that the checksum is not the same. $ mongodump --quiet --db backup --out . $ tar -cf backup1.tar ...
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6 votes
2 answers
2k views

zfs checksum error in raidz1 vdev but not in disk

I am backing up data stored in a zpool consisting of a single raidz vdev with 2 hard disks. During this operation, I got checksum errors, and now the status looks as follows: pool: tmp_zpool state:...
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0 votes
1 answer
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FCIV recursive verification on a xml file

Copying files folder to files_copy folder, one wants to check the files were copied correctly. Fciv.exe permits to make an xml database of the original files and then compare it to the copied ...
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3 votes
1 answer
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Is there any reference for current binary file checksums (Ubuntu 12.04 LTS)

I'm using rkhunter to check my system regularly - Sometimes rkhunter output some warnings on file changes (after update e.g.) rkhunter gives me the new file checksum and the old one, but is there any ...
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2 votes
1 answer
564 views

Is it possible to disable zfs self-healing without disabling checksums?

I would like to disable ZFS self-healing in case of scenario as described here: https://pthree.org/2013/12/10/zfs-administration-appendix-c-why-you-should-use-ecc-ram/ In that scenario bad RAM (ECC or ...
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2 votes
2 answers
6k views

Check if MySQL Replication is in sync

The MySQL documentation about CHECKSUM TABLE is very minimalistic. My question: Is CHECKSUM TABLE a good way of checking if a MySQL Slave Table is in sync with the master? In other words: Can i use ...
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0 votes
0 answers
55 views

apt/maven/npm checksum failure on amazon ec2

I'm recently encountering multiple download checksum failures when booting ec2 machine. This manifests itself with sporadic failures of apt, maven and npm installs. In one case that the pom checksum ...
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3 votes
1 answer
2k views

Does NTFS / Windows as OS performs checksumming on file movement operations by default?

That's what I can't find Does NTFS / Windows as OS performs checksumming on file movement operations by default? alike ZFS or somehow else...
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2 votes
1 answer
1k views

Check all debian binaries against the checksum of the original

I would like to check all binaries on my server against dpkg -e <path_to_deb_package> <destination> (for example rkhunter could do this check against the originals when doing probupdate)...
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0 votes
2 answers
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Unable to POST/Upload files to a PHP page

I have a weird problem when I try to post contents or upload files by php to my server. After submitting the form it sleeps for a while then shows a page loading error. I tried different contents and ...
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2 votes
4 answers
3k views

Why is the TCP checksum inverted?

From the Wikipedia page: The checksum field is the 16 bit one's complement of the one's complement sum of all 16-bit words in the header and text. Why, after summing the 16-bits in the header and ...
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1 answer
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Tools for compare huge number of files in two different server [closed]

I have question. Have you ever use any tools that can fast compare the identical of huge number of files (let's say thousands files with total size up to 15 GB) in two different windows 2003 server? I ...
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5 votes
1 answer
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Is it possible to access the ZFS checksums to compare files

I have a FreeNAS 8 machine (FreeBSD 8.2-RELEASE-p1) with two different shares on it. I'm migrating files from Share1 to Share2. The Shares have different directory structures and naming conventions. I'...
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16 votes
2 answers
13k views

How to get checksum data integrity on ext4?

On file systems like btrfs you can preform a scrub, which will go though all the data to see if the data still matches the file system checksum. I would like to check the data on ext4 if it is ...
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TCP: Redundant checksum avoidance specification

TCP provides a mechanism to change the checksum scheme used by the two parties in a TCP session. There are four allowed checksum schemes according to this table, the last being "Redundant ...
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1 vote
2 answers
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Is the TCP checksum over the payload?

I was somehow convinced that the TCP checksum was a header checksum (similar to the IP checksum), but I'm now having doubts reading the Wikipedia article: The checksum field is the 16 bit one's ...
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-1 votes
1 answer
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MD5 for Git's git-credential-osxkeychain executable? [closed]

This question copied over from Super-User, where it was apparently unwelcome. Anyway, asked and answered: I'm setting up a GitHub account and have downloaded Git's git-credential-osxkeychain ...
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2 votes
1 answer
721 views

Gzip command to produce exact same output than tar -cvzf?

I did thought the following commands where equivalent, but they produce different checksums: tar -cvzf ... and tar -cvf ...; gzip ... does not produce the same output. sha1sumdiffers. What would be ...
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1 vote
3 answers
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Install Java EE 6 on CentOS 6

Having problems installing Java EE 6 in CentOS 6 x32. I have removed all previous version of Java and freshly installed temporally jdk1.6.0_34. So my $PATH variable goes to: /usr/lib/qt-3.3/bin:/...
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1 vote
1 answer
346 views

Rsync backups: checksums don’t match

I am a little confused by this although diff –rq dir/ dir1/ does not show a difference This rsync is to backup the directory rsync -avrREz --delete --links -e "ssh -l user" --delete dir/ site....
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3 votes
2 answers
1k views

Checksumming mysql replicas over ssl

After hours of struggling to understand the way percona toolkits (2.1) pt-table-checksum works, I try to try you. Situation Running MySQL replication (Master-active:Master:passive) Slave user is ...
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3 votes
1 answer
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huge packet loss and checksum errors

Our 2008 server began to work very slowly within 2 weeks. Our web sites (iis 7.5) are loading very slowly and sometimes its freezing. We began testing with wireshark and saw that our packets are ...
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2 votes
2 answers
1k views

Network boot (PXE) and caching of files

I'm looking into changing how to deploy network boot for clusters of servers. My worry is network transfer since not all boxes will be close to boot servers and network might be slow. The machines ...
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4 votes
1 answer
373 views

What would cause a successful file transfer to have checksums not match? [closed]

After very large file transfers (this only happens with 10gig+ files) to a specific system, the receiving system would have a mismatched checksum of the file. The transfer seems to have happened ...
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0 votes
1 answer
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how to properly compare the same two large files on two different servers byte for byte?

So I have two servers with the same 10gb gzip file on each. On one server it unzips fine. On the other there are crc errors. The file sizes are the exact same. the systems are exactly the same ...
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1 vote
2 answers
1k views

Windows checksums?

I am looking for a official source for windows checksums (in my special case windows xp). Normally I use the "Microsoft Benefit Portal" for that, but seems like it's gone, at least I can't find it ...
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5 votes
2 answers
9k views

Checksumming to verify rsync transfers

So rsync runs some checksums in the course of deciding what to transfer (i.e. what blocks within a file). But is there any reason to trust the file you end up with on the receive side any more than ...
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3 votes
3 answers
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CentOS 6 on Hyper-V - network adapter doesn't work (no checksum feature)

I have installed CentOS 6.0 on Hyper-V Server 2008 R2 SP1. VM has only synthetic network adapter enabled. Installation was successfull (without any network), then I installed Linux Integration ...
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