Easiest way to specify the outgoing IP on a VPS with multiple IPs?

user123

My knowledge of nix is minimal (I can usually do/google enough to do basic things like run automated installers, manually go through and modify basic config files, follow guides, etc). My question is essentially the same as what another person posted here: http://www.questionhub.com/ServerFault/128169

Actually, there are two questions:

Q1) If I have a VPS with two or more IPv4 addresses, what is the easiest way to set it up such that if I connect (for the purpose of SSH tunneling) to IP 1, the outgoing IP will be IP 1, that connecting to IP2 will use IP2 as the outgoing IP, etc. For this question, I specifically want to SSH tunnel, not use a VPN.

Q2) What would be the easiest way to achieve the same set up as in Q1, except through (password-protected) SOCKS5 proxies instead of SSH tunneling?

I'm interested in both scenarios because while the setup in #2 would be more convenient (and fine for random surfing), I would presume that #1 is more secure (for example, if I am surfing private data from public wifi).

Thanks for letting me pick your collective nose brains .

user123

Anyone?

dhamaniasad

Which distro do you use?

user123

@dhamaniasad said:
Which distro do you use?

Debian 6 (32-bit) is my preferred default

FrankZ

I don't do much in Debian, so I will not give routing advise, but have you tried iptables nat?

If the service is running on < IP2 >

iptables -t nat -A POSTROUTING -s < IP2 > -j SNAT --to-source < IP2 >

joereid

SNAT is the only way

user123

Thanks, FrankZ and joereid. I'll try that command once the second IP is set up on my VPS.

cosmicgate

Like everyone said SNAT is the way to go

DalComp

change main IP in SolusVM?

user123

@FrankZ said:
I don't do much in Debian, so I will not give routing advise, but have you tried iptables nat?

If the service is running on < IP2 >

iptables -t nat -A POSTROUTING -s < IP2 > -j SNAT --to-source < IP2 >

@FrankZ @joereid @cosmicgate
The command didn't work . IP1 still shows up as the IP when I surf after connecting to the VPS through IP2.

@DalComp said:
change main IP in SolusVM?

I want to be able to use both IPs.

SegmentationFault

You can try snat/postrouting by uid:

adduser proxy1
id -u proxy1
iptables -m owner -t nat -A POSTROUTING --uid-owner <proxy1 uid> -j SNAT --to <IP1>
adduser proxy2
id -u proxy2
iptables -m owner -t nat -A POSTROUTING --uid-owner <proxy2 uid> -j SNAT --to <IP2>

Then you can connect through SSH/tunnel/etc with proxy1 to use IP1 and proxy2 to use IP2

user123

@SegmentationFault said:
You can try snat/postrouting by uid:

adduser proxy1
id -u proxy1
iptables -m owner -t nat -A POSTROUTING --uid-owner <proxy1 uid> -j SNAT --to <IP1>
adduser proxy2
id -u proxy2
iptables -m owner -t nat -A POSTROUTING --uid-owner <proxy2 uid> -j SNAT --to <IP2>

Then you can connect through SSH/tunnel/etc with proxy1 to use IP1 and proxy2 to use IP2

Thanks, this worked