Bug ID 816205: IPsec passthrough scenario may not forward ICMP unreachable messages from the server-side

Last Modified: Sep 14, 2023

Affected Product(s):
BIG-IP LTM(all modules)

Known Affected Versions:
12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 12.1.4, 12.1.4.1, 12.1.5, 12.1.5.1, 12.1.5.2, 12.1.5.3, 12.1.6, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 13.1.3, 13.1.3.1, 13.1.3.2, 13.1.3.3, 13.1.3.4, 13.1.3.5, 13.1.3.6, 13.1.4, 13.1.4.1, 13.1.5, 13.1.5.1, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.0.1, 14.0.1.1, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 14.1.2.4, 14.1.2.5, 14.1.2.6, 14.1.2.7, 14.1.2.8, 14.1.3, 14.1.3.1, 14.1.4, 14.1.4.1, 14.1.4.2, 14.1.4.3, 14.1.4.4, 14.1.4.5, 14.1.4.6, 14.1.5, 14.1.5.1, 14.1.5.2, 14.1.5.3, 14.1.5.4, 14.1.5.6, 15.0.0, 15.0.1, 15.0.1.1, 15.0.1.2, 15.0.1.3, 15.0.1.4

Fixed In:
15.1.0

Opened: Aug 20, 2019

Severity: 3-Major

Symptoms

ICMP protocol 50 unreachable messages are not forwarded from the server-side to the client-side when a SNAT Virtual Server handles ESP flows that are not encapsulated in UDP port 4500 (RFC 3948). Other ICMP messages related to the server-side ESP flow may be similarly affected.

Impact

ICMP packets arriving on the server-side are not forwarded to the client-side.

Conditions

-- BIG-IP system is forwarding ESP (protocol 50) packets. -- Virtual Server is configured with a SNAT pool or automap. -- The server-side IPsec peer sends ICMP protocol errors in response to the ESP packets.

Workaround

Option 1: -- Enable NAT Detection (RFC 3947) on the IPsec peers. NOTE: NAT Detection (RFC 3947) is the correct way to implement IPsec peers when network address translation occurs between the two IPsec peers. Option 2: -- Remove NAT from the Virtual Server. -- Set the following sys db values: # tmsh modify sys db ipsec.lookupip value "enable" # tmsh modify sys db ipsec.lookupspi value "disable" NOTE: The sys db settings in option 2 do not resolve the ICMP issue if NAT is configured on the Virtual Server.

Fix Information

ICMP protocol 50 unreachable messages from the server-side are forwarded to the client-side.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips