OpenVPN lifetime of ip addresses within VPN Pool (SSL)

Question

How long is the lifetime of assigned IP adresses within VPN Pool (SSL)? Is it infinite as long as the VPN Pool (SSL) is not exhausted? 
 I ask because I use SNAT to masquerade IP addresses from VPN Pool (SSL) to Internal (Network). So I suppose the only way for communication between remote access clients is to use the IP addresses of VPN Pool (SSL). Or should I better configure and activate DNS resolution via Sophos UTM to get IP addresses from VPN Pool (SSL) via DNS resolution?

Udo Eber · Accepted Answer

Hey BAlfson, 
 yes when you leave "Allow multiple concurrent connections per user" activated clients get different ip addresses. But if you deactivate it and your number of VPN Pool (SSL) addresses is not exhausted the vpn clients get every time the same ip address. I know that behaviour from Endian Firewall and emmosophos confirmed it for Sophos UTM with his post 7 Jul 2020 11:03 PM in this thread: 
 The Pool of addresses is managed by OpenVPN and not the UTM DHCP, but basically, once you disconnect from the SSLVPN the IP is free, so yes it can be infinite as long as is not exhausted the max it can handle is /16. 
 Greetings Udo