[root@ns1 ~]# telnet gmail-smtp-in.l.google.com 25
Trying 172.217.197.27…
telnet: connect to address 172.217.197.27: Connection timed out
Trying 2607:f8b0:400d:c0f::1b…
telnet: connect to address 2607:f8b0:400d:c0f::1b: Network is unreachable

please help

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1 answer

Hi @eleetgeeks,

It’s possible you you need to allow outgoing TCP traffic on port 25

iptables -I INPUT -p tcp -m tcp --dport 25 -j ACCEPT

Additionally, you can further read this DigitalOcean article explaining more about Iptables and what they are - https://www.digitalocean.com/community/tutorials/iptables-essentials-common-firewall-rules-and-commands

Regards,
KDSys

by Mitchell Anicas
Iptables is the software firewall that is included with most Linux distributions by default. This cheat sheet-style guide provides a quick reference to iptables commands that will create firewall rules are useful in common, everyday scenarios. This includes iptables examples of allowing and blocking various services by port, network interface, and source IP address.
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