ssh batch execution

I always forget correct syntax for this:

ssh -o BatchMode=yes -o LogLevel=ERROR -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no user@host cmd

Traefik wildcard TLS with Digital Ocean DNS provider

version: "3.5"

services:
  gateway:
    image: traefik:2.4
    restart: always
    environment:
     DO_AUTH_TOKEN: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    command:
      - --providers.docker
      - --providers.docker.exposedbydefault=false
      - --entrypoints.http.address=:80
      - --entrypoints.https.address=:443
      - --certificatesresolvers.le.acme.httpchallenge=false
      - --certificatesresolvers.le.acme.httpchallenge.entryPoint=http
      - --certificatesresolvers.le.acme.dnschallenge=true
      - --certificatesresolvers.le.acme.dnschallenge.provider=digitalocean
      - --certificatesresolvers.le.acme.dnschallenge.delaybeforecheck=0"
      - --certificatesResolvers.le.acme.storage=/acme/acme.json
     #- "--certificatesResolvers.le.acme.caServer=https://acme-staging-v02.api.letsencrypt.org/directory"
    ports:
      - 80:80
      - 443:443
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - acme:/acme

  default:
    image: nginx:stable
    restart: always
    labels:
      - traefik.enable=true
      - traefik.http.middlewares.redirect.redirectscheme.scheme=https
      - traefik.http.routers.app-http.rule=HostRegexp(`{default:.*}`)
      - traefik.http.routers.app-http.entrypoints=http
      - traefik.http.routers.app-http.middlewares=redirect
      - traefik.http.routers.app-https.rule=HostRegexp(`{default:.*}`)
      - traefik.http.routers.app-https.entrypoints=https
      - traefik.http.routers.app-https.tls=true
      - traefik.http.routers.app-https.tls.certresolver=le
      - traefik.http.routers.app-https.tls.domains[0].main=test.example.com
      - traefik.http.routers.app-https.tls.domains[0].sans=*.test.example.com,other.example.pl,*.other.example.pl
    volumes:
      - ./:/usr/share/nginx/html

volumes:
  acme:
# vim: set tabstop=2 shiftwidth=2 expandtab autoindent indentexpr= nosmartindent :

CentOS 7/8 UEFI with ESP on RAID1

Kickstart configuration for RAID1 setup on UEFI firmware.

clearpart --all --initlabel 
part raid.A0 --fstype=raid --ondisk=sda --size=512
part raid.A1 --fstype=raid --ondisk=sda --size=200
part raid.A2 --fstype=raid --ondisk=sda --size=1 --grow
part raid.B0 --fstype=raid --ondisk=sdb --size=512
part raid.B1 --fstype=raid --ondisk=sdb --size=200
part raid.B2 --fstype=raid --ondisk=sdb --size=1 --grow
raid /boot     --device=0 --fstype=ext4  --level=1 raid.A0 raid.B0
raid /boot/efi --device=1 --fstype=efi   --level=1 raid.A1 raid.B1
raid pv.1      --device=2 --fstype=lvmpv --level=1 raid.A2 raid.B2
volgroup storage pv.1
logvol /    --fstype=ext4 --name=root --vgname=storage --size=8192
logvol swap --name=swap   --vgname=storage --size=8192
logvol /srv --fstype=xfs  --name=srv --vgname=storage --size=1 --grow

All partitions are marked as RAID type (no esp or boot).

MDRAID for  ESP is created with 1.0 metadata format (metadata at the end of the partition).

Apache + PHP - deny policy

This is sample config for apache + php (mod_php) which by default blocks all .php and allow only specified locations:

php_admin_value engine off
<FilesMatch "\.php$">
  Deny from All
</FilesMatch>
<Location /index.php>
  Allow From All
  php_admin_value engine on
</Location>
<Location /sample/>
 Allow From All
 php_admin_value engine on
</Location>

This assume there is catch all to index.ph somewhere (.htaccess or vhost).

IPSec policy via plain old setkey

In old days I sometimes used IPSec keying (PSK) via manual rules (no IKE at all). I needed sample config for some PoC stuff. So for "future" use: On one side:

#!/usr/sbin/setkey -f
flush;
spdflush;
add IP1.IP1.IP1.IP1 IP2.IP2.IP2.IP2 esp 0x1000 -m tunnel -E blowfish-cbc "<32 chars>" -A hmac-sha1 "<20 chars>";
add IP2.IP2.IP2.IP2 IP1.IP1.IP1.IP1 esp 0x2000 -m tunnel -E blowfish-cbc "<32 chars>" -A hmac-sha1 "<20 chars>";

spdadd 100.100.0.0/16 100.64.0.0/16  any -P in  ipsec esp/tunnel/IP1.IP1.IP1.IP1-IP2.IP2.IP2.IP2/require;
spdadd 100.64.0.0/16  100.100.0.0/16 any -P out ipsec esp/tunnel/IP2.IP2.IP2.IP2-IP1.IP1.IP1.IP1/require;

On other side:

#!/usr/sbin/setkey -f
flush;
spdflush;
add IP1.IP1.IP1.IP1 IP2.IP2.IP2.IP2 esp 0x1000 -m tunnel -E blowfish-cbc "<32 chars>" -A hmac-sha1 "<20 chars>";
add IP2.IP2.IP2.IP2 IP1.IP1.IP1.IP1 esp 0x2000 -m tunnel -E blowfish-cbc "<32 chars>" -A hmac-sha1 "<20 chars>";

spdadd 100.100.0.0/16 100.64.0.0/16  any -P out ipsec esp/tunnel/IP1.IP1.IP1.IP1-IP2.IP2.IP2.IP2/require;
spdadd 100.64.0.0/16  100.100.0.0/16 any -P in  ipsec esp/tunnel/IP2.IP2.IP2.IP2-IP1.IP1.IP1.IP1/require;

Change spdadd policy direction only.

What is my IP? DNS way...

What is my IP via custom DNS server:

dig @ip.socha.it tell-me-my-ip +short

Other use cases

dig @ip.socha.it ip +short
dig @ip.nauka.ga ip +short
dig @ip.automatus.cf ip +short

dig @ip.socha.it ip TXT +short 
dig @ip.socha.it ip TXT +short +tcp

What is my IP? The nginx way...

Pure nginx solution ;)

curl -sf ip.socha.it

or

curl -sf ip.socha.it/eol

Nginx configuration:

server {
        listen 80;
        server_name ip.socha.it;
        default_type "text/plain";
        location /eol {
          return 200 "$remote_addr\n";
        }
        location / {
          return 200 $remote_addr;
        }
}