AWS Network Limits and Limitations

It is good to know about the AWS network limits both for planning and troubleshooting: you can build your architecture to allow you to overcome these limits and it saves you time of troubleshooting when there is a failure or downtime in your network.

For example, an AWS VGW carries a hard limit of 100 BGP routes in total. When the BGP prefixes exceed 100, VGW randomly resets the BGP session, leading to unpredictable potential network downtime.

AWS publishes VPC limits at this link.

In addition to limits, there are limitations in functionality.

Below is a list of commonly asked limits and limitations by network engineers.




VPC Peering Limit per VPC


default limit is 50. Constrained also by route limit of 100

VPC Route entries in a route table


default is 50. Performance impact on 100 routes.

BGP prefix total on VGW


exceeding the limit results in random BGP resets

VGW instance size scaling

reset BGP

trigger a BGP downtime

DNAT function in VGW

not available

SNAT function in VGW

not available

NAT Gateway policies

not available

VPN connections per VPC


VPN traffic initiation

from on-prem

traffic must be initiated from on-prem to establish a VPN tunnel with VGW

VIF per Direct Connect


Inter region peering MTU size

1500 bytes

unlike intra region peering, there is no jumbo frame support, therefore inter region performance is maxed out at 5Gbps.

Outgoing SMTP traffic on port 25


you can send a request to lift the throttle.