Valheim – Linux Dedicated Server : How to define the Interface / public IP address to be used ?

Lazy devs binding on 0.0.0.0 ???

 
No way at the moment to define the @IP address to be used by the game.. 
 
Workaround : If your server has many network interfaces and/or public IP addresses, you can use Network Namespaces & iptables 
 
 

Example of script that should work

 
#!/bin/bash 
# !!! RUN ME AS ROOT USER !!! 
 
steamUser=steam 
steamGroup=${steamUser} 
steamHome=/home/${steamUser} 
valheimHome=${steamHome}/valheim 
valheimName=”My Server” 
valheimWorld=”Dedicated” 
valheimPass=”changeme!” 
publicIpAddr=w.x.y.z 
serverIfName=”eth0″ 
netNsName=”valheim_ns” 
vethNetwork=10.0.0.0/24 
vethRootName=”valheim_veth” 
vethRootAddr=10.0.1.1 
vethNsName=”valheim_ns_veth” 
vethNsAddr=10.0.1.2 
 
echo “*** steam install (if required) ***” 
 
if [[ $(grep “${steamUser}” /etc/passwd | sed -e ‘s/:.*//’) = “${steamUser}” ]]; then 
echo -e “User ${steamUser} exists” 
else 
useradd -m ${steamUser} 
fi 
 
if [[ ! -f ${steamHome}/steamcmd.sh ]]; then 
cd ${steamHome} 
curl -sqL http://”https://steamcdn-a.akamaihd.net/client/installer/steamcmd_linux.tar.gz” | tar zxvf – 
chown ${steamUser}.${steamGroup} -R ${steamHome} 
fi 
 
echo “*** valheim install (if required) ***” 
 
if [[ ! -d ${valheimHome} ]]; then 
cat << VALHEIM_INSTALL > ${steamHome}/valheim.install.sh 
#!/bin/bash 
# !!! RUN ME AS ${steamUser} USER !!! 
 
mkdir -p ${valheimHome} 
 
cd ${steamHome} 
 
${steamHome}/steamcmd.sh +login anonymous +force_install_dir ${valheimHome} +app_update 896660 validate +exit 
 
VALHEIM_INSTALL 
chmod 755 ${steamHome}/valheim.install.sh 
chown ${steamUser}.${steamGroup} ${steamHome}/valheim.install.sh 
su – ${steamUser} -c ${valheimHome}/valheim.install.sh 
fi 
 
echo “*** valheim start script ***” 
 
cat << VALHEIM_START > ${steamHome}/valheim.start.sh 
#!/bin/bash 
# !!! RUN ME AS ${steamUser} USER !!! 
 
export templdpath=\$LD_LIBRARY_PATH 
export LD_LIBRARY_PATH=./linux64:\$LD_LIBRARY_PATH 
export SteamAppId=892970 
 
echo “Updating” 
 
cd ${steamHome} 
${steamHome}/steamcmd.sh +login anonymous +force_install_dir ${valheimHome} +app_update 896660 +quit > ${steamHome}/valheim.update.log 2>&1 
 
echo “Workaround” 
 
cp -Rvvf ${steamHome}/linux64/steamclient.so ${valheimHome}/linux64/ 
 
echo “Starting” 
 
cd ${valheimHome} 
# NOTE: Minimum password length is 5 characters & Password cant be in the server name. 
# NOTE: You need to make sure the ports 2456-2458 is being forwarded to your server through your local router & firewall. 
./valheim_server.x86_64 -name “${valheimName}” -port 2456 -world “${valheimWorld}” -password “${valheimPass}” -public 1 > ${steamHome}/valheim.server.log 2>&1 
 
export LD_LIBRARY_PATH=\$templdpath 
 
VALHEIM_START 
chmod 755 ${steamHome}/valheim.start.sh 
chown ${steamUser}.${steamGroup} ${steamHome}/valheim.start.sh 
 
echo “*** network config ***” 
 
if [[ ! -d /sys/devices/virtual/net/${vethRootName} ]]; then 
ip netns add ${netNsName} 
ip link add ${vethNsName} type veth peer name ${vethRootName} 
ip link set ${vethRootName} up 
ip address add ${vethRootAddr}/24 dev ${vethRootName} 
ip link set ${vethNsName} netns ${netNsName} 
ip netns exec ${netNsName} ip link set dev lo up 
ip netns exec ${netNsName} ip link set dev ${vethNsName} up 
ip netns exec ${netNsName} ip address add ${vethNsAddr}/24 dev ${vethNsName} 
ip netns exec ${netNsName} route add default gw ${vethRootAddr} 
 
echo 1 > /proc/sys/net/ipv4/ip_forward 
iptables -t nat -A PREROUTING -d ${publicIpAddr} -p tcp -m multiport –dports 2456:2458 -j DNAT –to-destination ${vethNsAddr} 
iptables -t nat -A PREROUTING -d ${publicIpAddr} -p udp -m multiport –dports 2456:2458 -j DNAT –to-destination ${vethNsAddr} 
#iptables -A FORWARD -i ${serverIfName} -o ${vethRootName} -p tcp -m multiport –dports 2456:2458 -j ACCEPT 
#iptables -A FORWARD -i ${serverIfName} -o ${vethRootName} -p udp -m multiport –dports 2456:2458 -j ACCEPT 
iptables -A FORWARD -i ${serverIfName} -o ${vethRootName} -j ACCEPT 
iptables -A FORWARD -i ${vethRootName} -o ${serverIfName} -j ACCEPT 
iptables -t nat -A POSTROUTING -s ${vethNsAddr} ! -d ${vethNsAddr} -o ${serverIfName} -j SNAT –to-source ${publicIpAddr} 
fi 
 
echo “*** public address ***” 
ip netns exec ${netNsName} curl -s http://ipv4.icanhazip.com 
 
echo “*** starting server ***” 
ip netns exec ${netNsName} su – ${steamUser} -c ${valheimHome}/valheim.start.sh 
 
 

Usage & Notes

 
You should install first the following packages : lib32gcc1 tmux screen 
 
And add something like : 
 
/etc/systemd/system/valheim.service 
–8<————————————————– 
[Unit] 
Description=Valheim service 
Wants=network.target 
After=syslog.target network-online.target 
 
[Service] 
User=root 
Type=simple 
Restart=on-failure 
RestartSec=10 
KillMode=process 
WorkingDirectory=${valheimHome} 
ExecStart=${theSampleScriptFullName} 
 
[Install] 
WantedBy=multi-user.target 
–8<————————————————– 
Do not forget to update the values of ${valheimHome} and ${theSampleScriptFullName} to the real ones 
 
Before running : 
 
systemctl daemon-reload 
systemctl enable valheim.service 
 

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