FTP server is vsftpd.
network-security.acl.example.ftp.a7982d66
- Topology Description: ACL: Example: FTP: Active Mode, Passive Mode - Topology ID: ''a7982d66-91df-42e4-b74d-bd9c6cb77d14'' - Lab Password: EgkhdSc5mw ### Links Cisco: ACL: Example: FTP: Active Mode, Passive Mode [PG1X WIKI] https://pg1x.com/tech:network:cisco:security:network-security:acl:ftp:ftp
enp0s2
→ ens2
enp0s3
→ ens3
CML 2.1 Interface shows enp0s2, but actually interpreted interface name is ens2… Also, ens3
Issue: 1aa5d9f1 CML-P 2.1 refplat_p-20201020-fcs.iso Ubuntu 20.04(Focal) has wrong interface name
sudo apt install ftp
sudo apt install vsftpd
icmp or tcp icmp or tcp.port in {20 21}
configure terminal ! access-list 101 permit tcp host 10.1.1.200 host 10.2.2.201 eq ftp access-list 101 permit tcp host 10.1.1.200 host 10.2.2.201 eq ftp-data ! interface GigabitEthernet 0/0 ip access-group 101 in ! end
ping 10.2.2.201 ftp 10.2.2.201
cd /etc get passwd
384 2020-12-06 18:11:51.855600 10.2.2.201 10.1.1.200 FTP 113 Response: 227 Entering Passive Mode (10,2,2,201,77,92).
(A,B,C,D,E,F) E * 256 + F 77 * 256 + 92 = 19804
icmp or tcp
configure terminal ! access-list 102 permit tcp host 10.1.1.200 host 10.2.2.201 eq ftp ! ephemeral port access-list 102 permit tcp host 10.1.1.200 host 10.2.2.201 gt 1023 ! interface GigabitEthernet 0/0 ip access-group 102 in ! end
ping 10.2.2.201 ftp 10.2.2.201
passive cd /etc get passwd
active mode
512 2020-12-06 18:22:41.099560 10.1.1.200 10.2.2.201 FTP 91 Request: PORT 10,1,1,200,193,141
(A,B,C,D,E,F) E * 256 + F 193 * 256 + 141 = 49549
Frame 525: 70 bytes on wire (560 bits), 70 bytes captured (560 bits) on interface -, id 0 Ethernet II, Src: RealtekU_0f:67:18 (52:54:00:0f:67:18), Dst: RealtekU_0f:8c:15 (52:54:00:0f:8c:15) Internet Protocol Version 4, Src: 10.1.1.1, Dst: 10.1.1.200 Internet Control Message Protocol Type: 3 (Destination unreachable) Code: 13 (Communication administratively filtered) Checksum: 0x0239 [correct] [Checksum Status: Good] Unused: 00000000 Internet Protocol Version 4, Src: 10.1.1.200, Dst: 10.2.2.201 Transmission Control Protocol, Src Port: 49549, Dst Port: 20
passive mode
561 2020-12-06 18:24:55.938402 10.2.2.201 10.1.1.200 FTP 114 Response: 227 Entering Passive Mode (10,2,2,201,126,56).
(A,B,C,D,E,F) E * 256 + F 126 * 256 + 56 = 32312
icmp or tcp icmp or tcp.port in {20 21}
configure terminal ! access-list 103 permit tcp host 10.1.1.200 host 10.2.2.201 eq ftp access-list 103 permit tcp host 10.1.1.200 host 10.2.2.201 eq ftp-data established ! access-list 104 permit tcp host 10.2.2.201 eq ftp host 10.1.1.200 established access-list 104 permit tcp host 10.2.2.201 eq ftp-data host 10.1.1.200 ! interface GigabitEthernet 0/0 ip access-group 103 in interface GigabitEthernet 0/1 ip access-group 104 in ! end
active mode
898 2020-12-06 19:03:08.837097 10.1.1.200 10.2.2.201 FTP 89 Request: PORT 10,1,1,200,158,1
(A,B,C,D,E,F) E * 256 + F 158 * 256 + 1 = 40449
passive mode
933 2020-12-06 19:05:12.547046 10.2.2.201 10.1.1.200 FTP 115 Response: 227 Entering Passive Mode (10,2,2,201,113,245).
(A,B,C,D,E,F) E * 256 + F 113 * 256 + 245 = 29173
icmp or tcp
configure terminal ! access-list 105 permit tcp host 10.1.1.200 host 10.2.2.201 eq ftp ! ephemeral port access-list 105 permit tcp host 10.1.1.200 host 10.2.2.201 gt 1023 ! access-list 106 permit tcp host 10.2.2.201 eq ftp host 10.1.1.200 established ! ephemeral port access-list 106 permit tcp host 10.2.2.201 gt 1023 host 10.1.1.200 established ! interface GigabitEthernet 0/0 ip access-group 105 in interface GigabitEthernet 0/1 ip access-group 106 in ! end
1041 2020-12-06 19:15:46.744615 10.1.1.200 10.2.2.201 TCP 74 56806 → 21 [SYN] Seq=0 Win=64240 Len=0 MSS=1460 SACK_PERM=1 TSval=3824331117 TSecr=0 WS=128 1042 2020-12-06 19:15:46.747162 10.2.2.201 10.1.1.200 TCP 74 21 → 56806 [SYN, ACK] Seq=0 Ack=1 Win=65160 Len=0 MSS=1460 SACK_PERM=1 TSval=2415685427 TSecr=3824331117 WS=128
active mode
1067 2020-12-06 19:16:40.121042 10.1.1.200 10.2.2.201 FTP 91 Request: PORT 10,1,1,200,194,123
(A,B,C,D,E,F) E * 256 + F 194 * 256 + 123 = 49787
passive mode
1087 2020-12-06 19:18:29.953127 10.2.2.201 10.1.1.200 FTP 114 Response: 227 Entering Passive Mode (10,2,2,201,94,187). 1089 2020-12-06 19:18:29.953731 10.1.1.200 10.2.2.201 TCP 74 39482 → 24251 [SYN] Seq=0 Win=64240 Len=0 MSS=1460 SACK_PERM=1 TSval=3824494326 TSecr=0 WS=128 1090 2020-12-06 19:18:29.955526 10.2.2.201 10.1.1.200 TCP 74 24251 → 39482 [SYN, ACK] Seq=0 Ack=1 Win=65160 Len=0 MSS=1460 SACK_PERM=1 TSval=2415848637 TSecr=3824494326 WS=128
(A,B,C,D,E,F) E * 256 + F 94 * 256 + 187 = 24251