| Message Code | PIX-6-602103 |
| Severity | Information |
| Description | IPSEC: Received an ICMP Destination Unreachable from src_addr with suggested PMTU of rcvd_mtu; PMTU updated for SA with peer peer_addr, SPI spi, tunnel name username, old PMTU old_mtu, new PMTU new_mtu. |
| Explanation | This message is displayed when the MTU of an SA is changed. When a packet is received for an IPSec tunnel, the corresponding SA is located and the MTU is updated based on the MTU suggested in the ICMP packet. If the suggested MTU is greater than 0 but less than 256, then the new MTU is set to 256. If the suggested MTU is 0, the old MTU is reduced by 256 or it is set to 256, whichever value is greater. If the suggested MTU is greater than 256, then the new MTU is set to the suggested value. src_addr —IP address of the PMTU sender rcvd_mtu—Suggested MTU received in the PMTU message peer_addr —IP address of the IPSec peer spi—IPSec Security Parameters Index username—Username associated with the IPSec tunnel old_mtu—Previous MTU associated with the IPSec tunnel new_mtu—New MTU associated with the IPSec tunnel |
| User Action | No action required. |
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