Hello

Bitcoin Client Software and Version Number: Bitcoin core 0.20.0 (regtest)
Operating System: Linux Mint 19.1
Description of Problem:
I wrote a program which is communication over the network protocol (specified in https://en.bitcoin.it/wiki/Protocol_documentation) with a bitcoin node. More in detail sending getaddr messages. For the handshake at the beginning I have to send a version (and verack) message. When I run my own node on the main network everything works fine. But now I wanted to play around an use a regtest network instead. Doing my research i only found out, that i have to change the magic number. Doing this when sending a version message I get nothing back as response. Is there something else I have to consider when communication with a regtest node?.