Note: Please contact Sophos Professional Services if you require direct assistance with your specific environment.
This article focuses on best practices to configure Uplink Balancing and Multipath Rules for 2 or more WAN links.
Thanks to @BAlfson for great explanation about default multipath rule.
To distribute traffic evenly on 2 WAN links,
Target: WAN interface "WAN_200_225" is only used by 192.168.10.9 to access Internet, no other internal host/network can use it to access Internet.
Assume UTM has 3 WAN interfaces, traffic from an internal network needs to be loaded on 2 WAN interfaces only.
Sophos UTM: Uplink Balancing and Multipath rule, support.sophos.com/.../KB-000034635
Since upgrading from 9.510 to 9.6 we sometimes face strange Multipath issues. Since then, we have seen this multiple times, that reply packets are being sent out the wrong wan interface, which leads to asymetric routing.... I think this is still persistent. We use weight=0 for the secondary line, this is the setting, that the affected systems have in common... Really strange issue.
Maybe another issue was implemented, while solving this issue: