https://forums.hardwarezone.com.sg/...sg-isp-comparison-latest-promo-deals.6665380/
1. More about SIMBA as an ISP.
Main issues now for SIMBA, at least from the reports, are the following
1) Lack of support --> this can be a critical issue especially for average users who are not tech savvy
2) CGNAT without Static IPv4 add-on. SIMBA 10Gbps has native IPv6 which may help but it may still be an issue for those want to have a public IPv4 address. You can refer to the earlier discussion about CGNAT in this post.
3) There are some routing issues reported as well.
#2 (lack of support) is the main reason that I can not recommend SIMBA to average users as of now.
Power users know their use cases well -- so it is usually not an issue to go with their choice of ISPs.
But I would not recommend power users to go for SIMBA either because of #2 (CGNAT without static IPv4 add-on).
2. Issue with CGNAT (MR, VQ and SIMBA) and workarounds
https://forums.hardwarezone.com.sg/threads/myrepublic-fibre-part-5.4981088/page-340#post-149246011
Majority of users will be okay with CGNAT but some users get affected (eg: cannot do port forwarding or hosting services).
VQ/MR provide static IPv4 add-on for those who hit the limit of CGNAT.
Unfortunately SIMBA does not have that add-on. It provides public IPv6 for 10Gbps plan users as a potential work-around but not able to sort out all issues.
https://en.wikipedia.org/wiki/Carrier-grade_NAT
- Carrier-grade NAT usually prevents the ISP customers from using port forwarding, because the network address translation (NAT) is usually implemented by mapping ports of the NAT devices in the network to other ports in the external interface. This is done so the router will be able to map the responses to the correct device; in carrier-grade NAT networks, even though the router at the consumer end might be configured for port forwarding, the "master router" of the ISP, which runs the CGN, will block this port forwarding because the actual port would not be the port configured by the consumer.[7] In order to overcome the former disadvantage, the Port Control Protocol (PCP) has been standardized in the RFC 6887.
- In cases of banning traffic based on IP addresses, a system might block the traffic of a spamming user by banning the user's IP address. If that user happens to be behind carrier-grade NAT, other users sharing the same public address with the spammer will be inadvertently blocked.[7] This can create problems for forum and wiki administrators attempting to address disruptive actions of a single malicious user sharing an IP address with legitimate users.