The protocol behind ping, distinct from both UDP and TCP. Between peered VNets, the default AllowVnetInBound NSG rule permits it.
Also called Internet Control Message Protocol.
In the Ultra Transcenders books
AZ-104AZ-700SC-500AZ-900SC-900AZ-802MD-102
Each book explains ICMP in context, with comparison tables and the common traps.
Terms in this definition
- UDP
A transport protocol that sends data without establishing a connection.
- TCP
A transport protocol that is connection-oriented.
- AllowVNetInBound
Built-in NSG inbound rule at priority 65000 that admits anything from the VirtualNetwork service tag, which also covers peered VNets.
- Default security rules
Built-in NSG rules at priorities 65000-65500: AllowVnetInBound, AllowAzureLoadBalancerInBound and DenyAllInBound, plus AllowVnetOutBound, AllowInternetOutBound and DenyAllOutBound. Removal is impossible; custom rules at 100-4096 take precedence.
Related terms
- AH
Short for Authentication Header, an IPsec protocol that verifies the sender and integrity of an entire IP packet but leaves it unencrypted. Network security group rules can filter on it, as they can on TCP, UDP, ICMP and ESP.
- Network Watcher NSG diagnostics
Covers cases IP flow verify cannot, simulating a flow (ICMP too) against a VM, NIC, scale set NIC or Application Gateway v2 to report allow or deny and the rules involved.
- NSG diagnostics
Tests a simulated flow against each applicable Virtual Network Manager security admin rule and NSG rule, then gives allow or deny with the deciding rule. Scale sets and ICMP are supported.
- Test group
In Connection Monitor, a bundle of sources, destinations and test configurations using TCP, ICMP or HTTP. Test groups live in a monitor, with one monitor per source region.