How to connect to a IPv6 service using IPv4 connection on CentOS 7?
I'm trying to work out how to connect an inbound IPv4 connection to a port listening on a IPv6 port on a CentOS box. No amount of Googling is helping me. :-(
To demonstrate on a vanilla CentOS 7 server:
- Confirm
bindV6onlyis disabled
$ cat /proc/sys/net/ipv6/bindv6only
0
- Run netcat listening on a IPv6 port
nc -lvn6p 80
- On another shell, attempt to telnet to the port via IPv4
telnet 127.0.0.1 80
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused
Further information
- Trying to connect via IPv6 works as expected. e.g. telnet ::1 80
- However everything I'm reading suggests that Linux-based IPv6 sockets should accept IPv4 connections too if net.ipv6.bindv6only is disabled in sysctl, which it is.
- I've tried Socket CAT, it works but isn't an elegant solution and requires a separate service to be configured. e.g.
socat TCP4-LISTEN:80,reuseaddr,fork TCP6:[::1]:80
ref: https://sysctl-explorer.net/net/ipv6/bindv6only/
ref: https://stackoverflow.com/questions/6343747/ipv6-socket-creation
Many thanks :-)
centos networking tcp ipv6 ipv4
asked 3 mins ago
Nick WiltonNick Wilton
1
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I'm trying to work out how to connect an inbound IPv4 connection to a port listening on a IPv6 port on a CentOS box. No amount of Googling is helping me. :-(
To demonstrate on a vanilla CentOS 7 server:
- Confirm
bindV6onlyis disabled
$ cat /proc/sys/net/ipv6/bindv6only
0
- Run netcat listening on a IPv6 port
nc -lvn6p 80
- On another shell, attempt to telnet to the port via IPv4
telnet 127.0.0.1 80
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused
Further information
- Trying to connect via IPv6 works as expected. e.g. telnet ::1 80
- However everything I'm reading suggests that Linux-based IPv6 sockets should accept IPv4 connections too if net.ipv6.bindv6only is disabled in sysctl, which it is.
- I've tried Socket CAT, it works but isn't an elegant solution and requires a separate service to be configured. e.g.
socat TCP4-LISTEN:80,reuseaddr,fork TCP6:[::1]:80
ref: https://sysctl-explorer.net/net/ipv6/bindv6only/
ref: https://stackoverflow.com/questions/6343747/ipv6-socket-creation
Many thanks :-)
centos networking tcp ipv6 ipv4
asked 3 mins ago
Nick WiltonNick Wilton
1
New contributor
Nick Wilton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
I'm trying to work out how to connect an inbound IPv4 connection to a port listening on a IPv6 port on a CentOS box. No amount of Googling is helping me. :-(
To demonstrate on a vanilla CentOS 7 server:
- Confirm
bindV6onlyis disabled
$ cat /proc/sys/net/ipv6/bindv6only
0
- Run netcat listening on a IPv6 port
nc -lvn6p 80
- On another shell, attempt to telnet to the port via IPv4
telnet 127.0.0.1 80
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused
Further information
- Trying to connect via IPv6 works as expected. e.g. telnet ::1 80
- However everything I'm reading suggests that Linux-based IPv6 sockets should accept IPv4 connections too if net.ipv6.bindv6only is disabled in sysctl, which it is.
- I've tried Socket CAT, it works but isn't an elegant solution and requires a separate service to be configured. e.g.
socat TCP4-LISTEN:80,reuseaddr,fork TCP6:[::1]:80
ref: https://sysctl-explorer.net/net/ipv6/bindv6only/
ref: https://stackoverflow.com/questions/6343747/ipv6-socket-creation
Many thanks :-)
centos networking tcp ipv6 ipv4
asked 3 mins ago
Nick WiltonNick Wilton
1
New contributor
Nick Wilton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I'm trying to work out how to connect an inbound IPv4 connection to a port listening on a IPv6 port on a CentOS box. No amount of Googling is helping me. :-(
To demonstrate on a vanilla CentOS 7 server:
- Confirm
bindV6onlyis disabled
$ cat /proc/sys/net/ipv6/bindv6only
0
- Run netcat listening on a IPv6 port
nc -lvn6p 80
- On another shell, attempt to telnet to the port via IPv4
telnet 127.0.0.1 80
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused
Further information
- Trying to connect via IPv6 works as expected. e.g. telnet ::1 80
- However everything I'm reading suggests that Linux-based IPv6 sockets should accept IPv4 connections too if net.ipv6.bindv6only is disabled in sysctl, which it is.
- I've tried Socket CAT, it works but isn't an elegant solution and requires a separate service to be configured. e.g.
socat TCP4-LISTEN:80,reuseaddr,fork TCP6:[::1]:80
ref: https://sysctl-explorer.net/net/ipv6/bindv6only/
ref: https://stackoverflow.com/questions/6343747/ipv6-socket-creation
Many thanks :-)
centos networking tcp ipv6 ipv4
centos networking tcp ipv6 ipv4
asked 3 mins ago
Nick WiltonNick Wilton
1
New contributor
Nick Wilton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 mins ago
Nick WiltonNick Wilton
1
New contributor
Nick Wilton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 mins ago
Nick WiltonNick Wilton
1
New contributor
Nick Wilton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 mins ago
Nick WiltonNick Wilton
1
asked 3 mins ago
Nick WiltonNick Wilton
1
1
New contributor
Nick Wilton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Nick Wilton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Nick Wilton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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