With o2 DSL connections, only PPPoE dial-up is possible. Exactly one public IPv4 address is assigned. IPv4 addresses are a scarce commodity, a second public IPv4 address is therefore not available. If this is absolutely desired (I cannot imagine for what purpose), an additional DSL connection would have to be made. 

Hello @Stratis, welcome back to our o2 community :-)

Since another IP is mostly used for incoming traffic, maybe a Dynamic DSN Service that can map an individual Domain Name to your IP address may be an alternative? :-)

Also all tariffs that have been activated within the last four years include DualStack with an IPv6 addressrange, that could work, too.

Regards,

Lars