TL;DR
ss -tulpn | grep -v "::1" | grep -v "127.0.0.1"
Welcome to my world
TL;DR
ss -tulpn | grep -v "::1" | grep -v "127.0.0.1"
When ssh into a server I want to start directly tmux or use an existing session.
ssh example.local -t "tmux a || tmux"
While trying to connect to an older esxi server I got the error message Unable to negotiate with 1.2.3.4 port 22: no matching host key type found. Their offer: ssh-rsa,ssh-dss
I was wondering.
The solution $EDITOR ~/.ssh/config
Host 1.2.3.4 User root HostKeyAlgorithms=+ssh-dss
The error message on the proxmox gui
() Job for [email protected] failed. See "systemctl status [email protected]" and "journalctl -xe" for details. TASK ERROR: command '/bin/systemctl start ceph-mgr@pve-03' failed: exit code 1
The error message from systemctl
[email protected]: Start request repeated too quickly. [email protected]: Failed with result 'start-limit-hit'.
Solve with
systemctl reset-failed ceph-mgr@pve-03 systemctl start ceph-mgr@pve-03
change pve-03 to your node name.
zfs send ... | ssh host2 zfs receive -s otherpool/new-fs
On the receiving side, get the opaque token with the DMU object #, offset stored in it
zfs send ... | ssh host2 zfs receive -s otherpool/new-fs zfs get receive_resume_token otherpool/new-fs # 1-e604ea4bf-e0-789c63a2...
Re-start sending from the DMU object #, offset stored in the token
zfs send -t 1-e604ea4bf-e0-789c63a2... | ssh host2 zfs receive -s otherpool/new-fs
If you don’t want to resume the send, abort to remove the partial state on the receiving system
zfs receive -A otherpool/new-fs
Edit
/etc/zfs/zed.d/zed.rc
uncomment
ZED_EMAIL_ADDR="[email protected]"
and add a valid email address.
uncomment
ZED_EMAIL_PROG="mail"
uncomment
ZED_EMAIL_OPTS="-s '@SUBJECT@' @ADDRESS@"
uncomment
ZED_NOTIFY_VERBOSE=0
if you want to get an email after every scrup set the value to 1
save the file and restart zed service
systemctl restart zed.service
A single disk zpool “test” crashed on my server (the disk died). It was just for testing, so nothing dramatic. However, when I rebooted the server I got the error message “failed Import ZFS pools by cache file”. A zpool destroy -f did not solve the problem. zpool status still showed the “test” pool. The other pool tank was still working.
What did help was
# disable the cache file for the existing pool(s) zpool set cachefile=none tank # delete the old pool file rm -rf /etc/zfs/zpool.cache # recreate if touch /etc/zfs/zpool.cache reboot # re-enable the cache zpool set cachefile=/etc/zfs/zpool.cache tank
Well, the cache file should be automatically updated when your pool configuration is changed, but with the crashed pool it did not.
After virtualizing a real computer with an old Linux I wanted to increase the partition size of the data drive. But I got this warning: resize2fs new size too large to be expressed in 32 bits
How to solve this? I started the VM with gparted-live.iso
# check file system e2fsck -f /dev/sdb1 # auf 64 bit ändern resize2fs -b /dev/sdb1 # increase partition .... wait :D / optional coffee resize2fs -p /dev/sdb1 # check file system e2fsck -f /dev/sdb1
Done :)
How to do things with iptables. Safety first: How to reset everything.
sudo iptables -F sudo iptables -X sudo iptables -t nat -F sudo iptables -t nat -X sudo iptables -t mangle -F sudo iptables -t mangle -X
sudo iptables -A INPUT -p tcp -s localhost --dport 3306 -j ACCEPT #mysql allow local sudo iptables -A INPUT -p tcp --dport 3306 -j REJECT --reject-with tcp-reset #mysql
The “REJECT –reject-with tcp-reset” looks to the outside like there is no service running. A “DROP” will show that there is a firewall / iptables working.
Blocking an IP range
sudo iptables -A bannedDownloader -s 14.120.0.0/16 -j DROP
Disallow NTP queries
sudo iptables -A INPUT -p udp -s localhost --dport 123 -j ACCEPT #ntp allow local sudo iptables -I INPUT -p udp --dport 123 -j REJECT #ntp
Block timestamp
sudo iptables -I INPUT 1 -p ICMP --icmp-type timestamp-request -j DROP sudo iptables -I INPUT 1 -p ICMP --icmp-type timestamp-reply -j DROP sudo iptables -A INPUT -p icmp --icmp-type 13 -j DROP
remove lines starting with string
:g/^1.2.3.4.*$//d
remove all empty lines
:g/^$/d
:g/profile/d
delete line that contains “profile”