Score:0

iptables --list showing 172-0-0-0.lightspeed.brhmal.sbcglobal.net/8

US flag
user969856

When i type sudo iptables --list i get this line appearing in my chain rules:

DROP all -- 172-0-0-0.lightspeed.brhmal.sbcglobal.net/8 anywhere

When i type sudo iptables -n --list i get this line instead:

DROP all -- 172.0.0.0/8 0.0.0.0/0

How come iptables tries to resolve this ip 172.0.0.0 to 172-0-0-0.lightspeed.brhmal.sbcglobal.net ?

I have tried to check 172.0.0.0 in the browser but it doesnt seem to resolve anything related.. thanks

Patrick Mevzek avatar
cn flag
Are you sure you didn't want to handle the `127.0.0.0/8` block in your rules instead of the `172.0.0.0/8` (just two digits swap)? The former has a special meaning, the latter not.
Score:0
fr flag

It looks like iptables --list does a reverse resolution of addresses and 172.0.0.0 actually resolves to 172-0-0-0.lightspeed.brhmal.sbcglobal.net:

vesemir:~> dig -x 172.0.0.0 +short
172-0-0-0.lightspeed.brhmal.sbcglobal.net.

The name also resolves back:

vesemir:~> dig 172-0-0-0.lightspeed.brhmal.sbcglobal.net +short
172.0.0.0

but it is highly unlikely there is anything there (it is network address, not a host address for any networks between /8 and /30).

-n option likely suppresses this resolution.

In short - nothing to worry about.

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