Check if port is opened
$ nc -zvw5 google.com 80
Connection to google.com 80 port [tcp/http] succeeded!
Get nameservers for the domain
nslookup -type=soa google.com # get primary nameserver
nslookup -type=ns google.com # get nameservers
dig +nocmd +noall +answer ns google.com # get nameservers using dig
Get A-record
dig google.com @ns1.google.com
Get domain TTL
dig +nocmd +noall +answer +ttlunits google.com @ns1.google.com
Get my IP Address
ifconfig eth1 | awk '/inet addr/{print substr($2,6)}'
View SSL Certificate on remote host
echo | openssl s_client -showcerts -servername gnupg.org -connect gnupg.org:443 2>/dev/null | openssl x509 -inform pem -noout -text
nmap -p 443 --script ssl-cert gnupg.org
Set interface zone permanently
Create a new if-up script
touch /etc/network/if-up.d/internal-zone && chmod +x $_ && vi $_
Put the following content and save (Shift+ZZ)
#!/bin/sh
if [ "$IFACE" != "lxcbr0" ]; then
exit 0
fi
firewall-cmd --zone=internal --change-interface="$IFACE"
docker0 interface isn't in the docker zone.sudo firewall-cmd --zone=docker --change-interface=docker0
Reboot and check
$ sudo firewall-cmd --get-active-zones
docker
interfaces: docker0
internal
interfaces: lxcbr0
...
File Transfer via network
Sender:
nc -v -l 80 < file.gz
nc -w 3 remote-ip 80 > file.gz
OpenWRT
Speed test with iperf3
# iperf3 -c ping.online.net -u -b 1G
Connecting to host ping.online.net, port 5201
[ 5] local xxx.xxx.xxx.xxx port 46361 connected to 62.210.18.40 port 5201
[ ID] Interval Transfer Bitrate Total Datagrams
[ 5] 0.00-1.00 sec 114 MBytes 956 Mbits/sec 82519
[ 5] 1.00-2.00 sec 111 MBytes 931 Mbits/sec 80335
[ 5] 2.00-3.00 sec 108 MBytes 909 Mbits/sec 78439
[ 5] 3.00-4.00 sec 109 MBytes 918 Mbits/sec 79250
[ 5] 4.00-5.00 sec 109 MBytes 914 Mbits/sec 78939
[ 5] 5.00-6.00 sec 109 MBytes 917 Mbits/sec 79203
[ 5] 6.00-7.00 sec 111 MBytes 930 Mbits/sec 80253
[ 5] 7.00-8.00 sec 110 MBytes 924 Mbits/sec 79802
[ 5] 8.00-9.00 sec 110 MBytes 923 Mbits/sec 79676
[ 5] 9.00-10.00 sec 111 MBytes 931 Mbits/sec 80381
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Jitter Lost/Total Datagrams
[ 5] 0.00-10.00 sec 1.08 GBytes 925 Mbits/sec 0.000 ms 0/798797 (0%) sender
[ 5] 0.00-10.00 sec 114 MBytes 95.7 Mbits/sec 0.009 ms 716162/798783 (90%) receiver
iperf Done.
Set up Dropbear public key authentication
ssh-copy-id root@192.168.1.1
ssh root@192.168.1.1
cp /root/.ssh/authorized_keys /etc/dropbear/
chmod 700 /etc/dropbear
chmod 600 /etc/dropbear/authorized_keys
IP Addresses daily log (cron job)
0 4 * * * echo "`date +%Y-%m-%d` $(ifconfig eth1 | awk '/inet addr/{print substr($2,6)}')" >> /root/ip.log
Port Mapping
ssh -L [LOCAL_IP:]LOCAL_PORT:DESTINATION:DESTINATION_PORT [USER@]SSH_SERVER
ssh -L 103306:db-server:3306 user@web.server.com