How to change MTU without ifconfig in ubuntu 18.04?

I need to change the MTU size in my newly installed ubuntu 18.04. This can be done with ifconfig. But i can not install ifconfig. Whenever i run command sudo apt install net-tools i get the following errors.

Err:1 bionic/main amd64 net-tools amd64 1.60+git20161116.90da8a0-1ubuntu1 Could not resolve 'archive.ubuntu.com'
E: Failed to fetch Could not resolve 'archive.ubuntu.com'
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

Then i tried sudo apt-get update and got the following

asif@asif-HP:~$ sudo apt-get update
Hit:1 stable InRelease
Err:2 bionic InRelease Could not resolve 'archive.ubuntu.com'
Err:3 bionic-updates InRelease Could not resolve 'archive.ubuntu.com'
Err:4 bionic-backports InRelease Could not resolve 'archive.ubuntu.com'
Err:5 bionic-security InRelease Could not resolve 'archive.ubuntu.com'
Err:6 bionic InRelease Could not resolve 'archive.canonical.com'
Reading package lists... Done
W: Failed to fetch Could not resolve 'archive.ubuntu.com'
W: Failed to fetch Could not resolve 'archive.ubuntu.com'
W: Failed to fetch Could not resolve 'archive.ubuntu.com'
W: Failed to fetch Could not resolve 'archive.canonical.com'
W: Failed to fetch Could not resolve 'archive.ubuntu.com'
W: Some index files failed to download. They have been ignored, or old ones used instead.

Actually i am trying change MTU size to solve the problem Could not resolve 'archive.canonical.com' so im kind of in deadlock. What do i do now?

N.B: I changed ubuntu archive server but always same error occurs.

2 Answers

You can use ip, which should already be installed. For example,

ip link set mtu 1200 eth0

You can use ifconfig command with mtu For example

ifconfig ens160 mtu 1458 up