On Tue, 31 Mar 2020 19:41:58 +1300 Peter <[email protected]> wrote:
> On 31/03/20 5:42 pm, Bob Proulx wrote:
> > The "$vpn" part is a variable was simply a placeholder for the IP
> > address of your VPN connected relayhost. It would be an IP address
> > like 93.184.216.34 but put in the IP address of your relay host that
> > is only accessible when the VPN is up.
> >
> > iptables -A OUTPUT -o 93.184.216.34 -m tcp --dport 25 -j ACCEPT
> > iptables -A OUTPUT -m tcp --dport 25 -j REJECT
> >
> > But replace 93.184.216.34 with the IP address of your VPN relay host.
> > I simply used an actual address inorder to clarify the example.
>
> Actually it's an interface name (such as tun0), not an IP address:
>
>
> [!] -o, --out-interface name
> Name of an interface via which a packet is going to be
> sent (for packets entering the FORWARD, OUTPUT and POSTROUTING chains).
> When the "!" argument is used before the
> interface name, the sense is inverted. If the
> interface name ends in a "+", then any interface which begins with this
> name will match. If this option is omitted, any
> interface name will match.
>
Hi,
Thanks very much! My VPN interface ic alled cscotun0 so I use:
$ sudo iptables -A OUTPUT -o cscotun0 -m tcp --dport 25 -j ACCEPT
iptables: Invalid argument. Run `dmesg' for more information.
I run dmesg but I am not sure what to find there.
My port is 25.
Btw,
$iptables -h
iptables v1.8.3
Usage: iptables -[ACD] chain rule-specification [options]
iptables -I chain [rulenum] rule-specification [options]
iptables -R chain rulenum rule-specification [options]
iptables -D chain rulenum [options]
iptables -[LS] [chain [rulenum]] [options]
iptables -[FZ] [chain] [options]
iptables -[NX] chain
iptables -E old-chain-name new-chain-name
iptables -P chain target [options]
iptables -h (print this help information)
Commands:
Either long or short options are allowed.
--append -A chain Append to chain
--check -C chain Check for the existence of a rule
--delete -D chain Delete matching rule from chain
--delete -D chain rulenum
Delete rule rulenum (1 = first) from chain
--insert -I chain [rulenum]
Insert in chain as rulenum (default 1=first)
--replace -R chain rulenum
Replace rule rulenum (1 = first) in chain
--list -L [chain [rulenum]]
List the rules in a chain or all chains
--list-rules -S [chain [rulenum]]
Print the rules in a chain or all chains
--flush -F [chain] Delete all rules in chain or all chains
--zero -Z [chain [rulenum]]
Zero counters in chain or all chains
--new -N chain Create a new user-defined chain
--delete-chain
-X [chain] Delete a user-defined chain
--policy -P chain target
Change policy on chain to target
--rename-chain
-E old-chain new-chain
Change chain name, (moving any references)
Options:
--ipv4 -4 Nothing (line is ignored by ip6tables-restore)
--ipv6 -6 Error (line is ignored by iptables-restore)
[!] --protocol -p proto protocol: by number or name, eg. `tcp'
[!] --source -s address[/mask][...]
source specification
[!] --destination -d address[/mask][...]
destination specification
[!] --in-interface -i input name[+]
network interface name ([+] for wildcard)
--jump -j target
target for rule (may load target extension)
--goto -g chain
jump to chain with no return
--match -m match
extended match (may load extension)
--numeric -n numeric output of addresses and ports
[!] --out-interface -o output name[+]
network interface name ([+] for wildcard)
--table -t table table to manipulate (default: `filter')
--verbose -v verbose mode
--wait -w [seconds] maximum wait to acquire xtables lock before
give up
--wait-interval -W [usecs] wait time to try to acquire xtables lock
default is 1 second
--line-numbers print line numbers when listing
--exact -x expand numbers (display exact values)
[!] --fragment -f match second or further fragments only
--modprobe=<command> try to insert modules using this command
--set-counters PKTS BYTES set the counter during insert/append
[!] --version -V print package version.
What is wrong here?
Many thanks again and best wishes,
Ranjan
