Junos IPSEC 隧道到 Azure 和 TCP-MSS

网络工程 杜松 网络安全 碎片化
2021-07-29 14:34:19

我正在配置 Juniper SRX 300 系列以建立到 Azure 的 IPSEC 隧道。

Azure Vnet 范围是 192.168.10.0/23

本地范围是 10.49.236.0/24。

配置:(敏感部分的相关位替换为$PART)

​security {
    ike {
        proposal ike-proposal-azure {
            authentication-method pre-shared-keys;
            dh-group group2;
            authentication-algorithm sha1;
            encryption-algorithm aes-256-cbc;
            lifetime-seconds 28800;
        }
        policy ike-policy-azure {
            mode main;
            proposals ike-proposal-azure;
            pre-shared-key ascii-text "$PSK";
        }
        gateway ike-gate-azure {
            ike-policy ike-policy-azure;
            address $AZUREGWPUBLICIP
            external-interface ge-0/0/0.0;
            version v2-only;
        }
    }
    ipsec {
        vpn-monitor-options {
            interval 10;
            threshold 10;
        }
        proposal ipsec-proposal-azure {
            protocol esp;
            authentication-algorithm hmac-sha1-96;
            encryption-algorithm 3des-cbc;
            lifetime-seconds 27000;
        }
        policy ipsec-policy-azure {
            proposals ipsec-proposal-azure;
        }
        vpn ipsec-vpn-azure {
            bind-interface st0.0;
            vpn-monitor {
                optimized;
            }
            ike {
                gateway ike-gate-azure;
                ipsec-policy ipsec-policy-azure;
            }
            establish-tunnels immediately;
        }
    }
    flow {
        tcp-mss {
            all-tcp {
                mss 1350;
            }
            ipsec-vpn {
                mss 1350;
            }
        }
    }

还有安全规则/策略允许进出 vpn 的流量和指向 st0.0 的 192,168.10.0/23 路由。问题:

PS C:\windows\system32> ping -l 1500 192.168.10.20

Pinging 192.168.10.20 with 1500 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 192.168.10.20:
    Packets: Sent = 4 Received = 0, Lost = 4 (100% loss),
Control-C
PS C:\windows\system32> ping -l 1400 192.168.10.20

Pinging 192.168.10.20 with 1400 bytes of data:
Reply from 192.168.10.20: bytes=1400 time=8ms TTL=127
Reply from 192.168.10.20: bytes=1400 time=7ms TTL=127

Ping statistics for 192.168.10.20:
    Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 7ms, Maximum = 8ms, Average = 7ms

到 Azure 主机的 SMB 流量也受到影响。在 azure 主机上运行 wireshark 时,我看到一堆碎片和碎片重组时间超过。 https://i.imgur.com/3c2c6uE.png

1个回答
set security ipsec vpn ipsec-vpn-azure df-bit copy

这解决了上述问题。