Skip to main content

SCP / SSH without password

By
To be able to log into a remote linux host without a password, you must generate a public / private key pair on the local host and copy the public key to the remote host. You would do this if you wanted to SCP some files via a script perhaps.

First, generate the key pair on the host that you are connecting from.

ssh-keygen -t dsa

Accept defaults.. can put passphrase if you wish for extra security.

Copy id_dsa.pub to the remote host somewhere. Then add it to the authorized_keys file under the home directory of the user that you are trying to log in as.

For instance if you are wanting to send a file to the remote server as user 'bob'...

copy the id_dsa.pub file to /tmp on the remote server
log in to the remote server as bob
cat /tmp/id_dsa.pub >> ~/.ssh/authorized_keys

Now you should be able to ssh or scp something to the remote host and not be prompted for a password.


Labels:

Comments

Post a Comment

Popular posts from this blog

Mikrotik Bridge Horizon

By
To achieve similar functionality to Cisco's private VLANS, where all ports are on the same L2 segment, but cannot exchange packets, you can use Mikrotik's Bridge Horizon feature. Basically, every port in a bridge is assigned a horizon value, and RouterOS will only forward frames to other interfaces in the bridge that have different horizon values. This means that you assign the same horizon value to the interfaces that you don't want to be able to communicate. For example, you want to bridge all your customers and use a single /24 subnet and the same gateway. Typically this is bad and poses a huge security risk, not to mention performance issues. If you assign the same horizon value to the customer interfaces, then the router will not forward traffic between customers. Customer A will not be able to ping Customer B. If you had a server, such as an IP-PBX that all customers needed to access, and you were lazy and added it to the bridge, then you would assign a diff...
Post a Comment
Read more

DHCP option 121

By
http://tools.ietf.org/html/rfc3442 This is used to add a classless  static route to the DHCP clients. To add option 121 to a Mikrotik DHCP server, it's value is specified in HEX. The format is as follows. 0xnnddddddddgggggggg where n=mask, d=destination, g=gateway. To convert ip address to HEX, you convert each octet, so 192=C0, 168=A8, 55=37, 1=01 You can use a tool such as  http://www.miniwebtool.com/ip-address-to-hex-converter/?ip=192.168.55.1 Example: To add a route to the destination network of 192.168.55.0/24 via gateway 172.16.10.1. /ip dhcp-server option add name=classlessroutes code=121 value=0x18C0A837AC100A01 where 18 is 24 in hex. *note: depending on the subnet mask, you may only need to specify 0-4 octets. In fact only the non-zero, or network portion of the subnet. Here is a table from the RFC. subnet mask Number of octets 0 0 1- 8 1 ...
Post a Comment
Read more

System History and the undo command

By
The history of system configuration changes is held until the next router shutdown. The invoked commands can be 'undone' using the /undo command. By invoking the command several times, the configuration changes can be 'undone' in reverse order they have been invoked. Use the /system history print command to see the list of performed actions: [MikroTik] system history> print Flags: U - undoable, R - redoable, F - floating-undo    ACTION                                   BY            POLICY           U nat rule changed                         admin         write            U nat rule changed                         admin         write ...
Post a Comment
Read more