Openssh 7+ ssh-dsa error fixed

The solution is to add the following line to ~/.ssh/config on every client machine (every machine where you run the SSH client): PubkeyAcceptedKeyTypes=+ssh-dss If the server is using OpenSSH 7.0 or newer, you’ll also need to add this line to /etc/ssh/sshd_config on each server machine.

Categorized as Big Data Tagged

the following resource is signed with a weak signature algorithm md5withrsa

So, after some digging, I just found a quick (but temporary) solution: Just comment out the setting of “jdk.jar.disabledAlgorithms” in the file of”lib/security/” (which is located at “/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/lib/security/, on my MacOS 10.12) # jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024 After that, the JNLP file will be running as usual again.

Categorized as Sysadmin Tagged

How Arp works in Linux

  To understand how ARP translates IP addresses to MAC addresses, consider the following example. Assume host A has an IP address of and a MAC address of fc:99:47:49:d4:a0, and wants to send a packet to host B with an IP address of Note that the network number is the same for both hosts, so host A is able to send frames directly… Continue reading How Arp works in Linux

How Vlan works in plain language

To understand how VLANs work, let’s consider VLAN applications in a traditional IT environment, where physical hosts are attached to a physical switch, and no virtualization is involved. Imagine a scenario where you want three isolated networks but you only have a single physical switch. The network administrator would choose three VLAN IDs, for example,… Continue reading How Vlan works in plain language

The meanings of SR、LRM、LR、ER and ZR

SR、LRM、LR、ER、ZR are terms used in fiber optic communications, stand for the transmission distance of the 10G modules. SR stands for Short Range, these transceivers support link length of 300m over multi-mode fiber and use 850nm lasers. LRM means Long Reach Multimode, these transceivers support distance up to 220m over multi-mode fiber and use 1310nm lasers.… Continue reading The meanings of SR、LRM、LR、ER and ZR

Docker under the hood

Many people think that docker is a kind of monolithic system and they hardly understand how internally it works. see the figure below