ProHoster > blog > Utawala > Jinsi ya kusuluhisha IPsec VPN ya nyumbani. Sehemu 1

Jinsi ya kusuluhisha IPsec VPN ya nyumbani. Sehemu 1

Jinsi ya kusuluhisha IPsec VPN ya nyumbani. Sehemu 1

Hali hiyo

Siku ya mapumziko. Nakunywa kahawa. Mwanafunzi alianzisha muunganisho wa VPN kati ya pointi mbili na kutoweka. Ninaangalia: kweli kuna handaki, lakini hakuna trafiki kwenye handaki. Mwanafunzi hapokei simu.

Niliweka kettle na kupiga mbizi kwenye utatuzi wa Lango la S-Terra. Ninashiriki uzoefu wangu na mbinu.

Data Chanzo

Tovuti mbili zilizotenganishwa kijiografia zimeunganishwa na handaki ya GRE. GRE inahitaji kusimbwa kwa njia fiche:

Jinsi ya kusuluhisha IPsec VPN ya nyumbani. Sehemu 1

Ninaangalia utendakazi wa handaki ya GRE. Ili kufanya hivyo, ninaendesha ping kutoka kwa kifaa R1 hadi kiolesura cha GRE cha kifaa R2. Hii ndio trafiki inayolengwa kwa usimbaji fiche. Hakuna jibu:

root@R1:~# ping 1.1.1.2 -c 4
PING 1.1.1.2 (1.1.1.2) 56(84) bytes of data.

--- 1.1.1.2 ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 3057ms

Ninaangalia magogo kwenye Gate1 na Gate2. Logi inaripoti kwa furaha kwamba handaki ya IPsec ilizinduliwa kwa mafanikio, hakuna shida:

root@Gate1:~# cat /var/log/cspvpngate.log
Aug  5 16:14:23 localhost  vpnsvc: 00100119 <4:1> IPSec connection 5 established, traffic selector 172.17.0.1->172.16.0.1, proto 47, peer 10.10.10.251, id "10.10.10.251", Filter 
IPsec:Protect:CMAP:1:LIST, IPsecAction IPsecAction:CMAP:1, IKERule IKERule:CMAP:1

Katika takwimu za handaki ya IPsec kwenye Gate1 naona kuwa kweli kuna handaki, lakini kihesabu cha Rсvd kimewekwa upya hadi sifuri:

root@Gate1:~# sa_mgr show
ISAKMP sessions: 0 initiated, 0 responded

ISAKMP connections:
Num Conn-id (Local Addr,Port)-(Remote Addr,Port) State Sent Rcvd
1 3 (10.10.10.251,500)-(10.10.10.252,500) active 1070 1014

IPsec connections:
Num Conn-id (Local Addr,Port)-(Remote Addr,Port) Protocol Action Type Sent Rcvd
1 3 (172.16.0.1,*)-(172.17.0.1,*) 47 ESP tunn 480 0

Ninasumbua S-Terra kama hii: Ninatafuta mahali pakiti zinazolengwa zimepotea kwenye njia kutoka R1 hadi R2. Katika mchakato (spoiler) nitapata kosa.

Utatuzi wa shida

Hatua ya 1. Nini Gate1 inapokea kutoka kwa R1

Ninatumia sniffer ya pakiti iliyojengwa - tcpdump. Ninazindua kinusi kwenye kiolesura cha ndani (Gi0/1 katika nukuu kama ya Cisco au eth1 kwenye nukuu ya Debian OS):

root@Gate1:~# tcpdump -i eth1

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth1, link-type EN10MB (Ethernet), capture size 262144 bytes
14:53:38.879525 IP 172.16.0.1 > 172.17.0.1: GREv0, key=0x1, length 92: IP 1.1.1.1 > 1.1.1.2: ICMP echo request, id 2083, seq 1, length 64
14:53:39.896869 IP 172.16.0.1 > 172.17.0.1: GREv0, key=0x1, length 92: IP 1.1.1.1 > 1.1.1.2: ICMP echo request, id 2083, seq 2, length 64
14:53:40.921121 IP 172.16.0.1 > 172.17.0.1: GREv0, key=0x1, length 92: IP 1.1.1.1 > 1.1.1.2: ICMP echo request, id 2083, seq 3, length 64
14:53:41.944958 IP 172.16.0.1 > 172.17.0.1: GREv0, key=0x1, length 92: IP 1.1.1.1 > 1.1.1.2: ICMP echo request, id 2083, seq 4, length 64

Ninaona kuwa Gate1 inapokea pakiti za GRE kutoka kwa R1. Ninaendelea.

Hatua ya 2. Gate1 hufanya nini na pakiti za GRE

Kutumia matumizi ya klogview naweza kuona kinachoendelea na pakiti za GRE ndani ya kiendeshi cha S-Terra VPN:

root@Gate1:~# klogview -f 0xffffffff

filtration result for out packet 172.16.0.1->172.17.0.1, proto 47, len 112, if eth0: chain 4 "IPsecPolicy:CMAP", filter 8, event id IPsec:Protect:CMAP:1:LIST, status PASS
encapsulating with SA 31: 172.16.0.1->172.17.0.1, proto 47, len 112, if eth0
passed out packet 10.10.10.251->10.10.10.252, proto 50, len 160, if eth0: encapsulated

Ninaona kuwa trafiki inayolengwa ya GRE (proto 47) 172.16.0.1 -> 172.17.0.1 ilikuja chini ya sheria ya usimbaji LIST katika ramani ya crypto ya CMAP na iliwekwa ndani. Ifuatayo, pakiti ilipitishwa (ilipitishwa). Hakuna trafiki ya majibu katika matokeo ya klogview.

Ninaangalia orodha za ufikiaji kwenye kifaa cha Gate1. Ninaona orodha moja ya ufikiaji ORODHA, ambayo inafafanua trafiki inayolengwa kwa usimbaji fiche, ambayo inamaanisha kuwa sheria za ngome hazijasanidiwa:

Gate1#show access-lists
Extended IP access list LIST
    10 permit gre host 172.16.0.1 host 172.17.0.1

Hitimisho: tatizo haliko kwenye kifaa cha Gate1.

Zaidi kuhusu klogview

Dereva wa VPN hushughulikia trafiki yote ya mtandao, sio tu trafiki ambayo inahitaji kusimbwa. Hizi ndizo jumbe zinazoonekana kwenye klogview ikiwa kiendeshi cha VPN kilichakata trafiki ya mtandao na kuisambaza bila kusimba:

root@R1:~# ping 172.17.0.1 -c 4

root@Gate1:~# klogview -f 0xffffffff

filtration result for out packet 172.16.0.1->172.17.0.1, proto 1, len 84, if eth0: chain 4 "IPsecPolicy:CMAP": no match
passed out packet 172.16.0.1->172.17.0.1, proto 1, len 84, if eth0: filtered

Ninaona kuwa trafiki ya ICMP (proto 1) 172.16.0.1->172.17.0.1 haikujumuishwa (hakuna mechi) katika sheria za usimbaji fiche za kadi ya crypto ya CMAP. Pakiti ilipitishwa (ilipitishwa) kwa maandishi wazi.

Hatua ya 3. Nini Gate2 inapokea kutoka Gate1

Ninazindua kinusi kwenye kiolesura cha WAN (eth0) Gate2:

root@Gate2:~# tcpdump -i eth0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
16:05:45.104195 IP 10.10.10.251 > 10.10.10.252: ESP(spi=0x30088112,seq=0x1), length 140
16:05:46.093918 IP 10.10.10.251 > 10.10.10.252: ESP(spi=0x30088112,seq=0x2), length 140
16:05:47.117078 IP 10.10.10.251 > 10.10.10.252: ESP(spi=0x30088112,seq=0x3), length 140
16:05:48.141785 IP 10.10.10.251 > 10.10.10.252: ESP(spi=0x30088112,seq=0x4), length 140

Ninaona kuwa Gate2 inapokea pakiti za ESP kutoka kwa Gate1.

Hatua ya 4. Gate2 hufanya nini na vifurushi vya ESP

Ninazindua matumizi ya klogview kwenye Gate2:

root@Gate2:~# klogview -f 0xffffffff
filtration result for in packet 10.10.10.251->10.10.10.252, proto 50, len 160, if eth0: chain 17 "FilterChain:L3VPN", filter 21, status DROP
dropped in packet 10.10.10.251->10.10.10.252, proto 50, len 160, if eth0: firewall

Ninaona kuwa pakiti za ESP (proto 50) zilidondoshwa (DROP) na sheria ya firewall (L3VPN). Ninahakikisha kuwa Gi0/0 ina orodha ya ufikiaji ya L3VPN iliyoambatanishwa nayo:

Gate2#show ip interface gi0/0
GigabitEthernet0/0 is up, line protocol is up
  Internet address is 10.10.10.252/24
  MTU is 1500 bytes
  Outgoing access list is not set
  Inbound  access list is L3VPN

Niligundua tatizo.

Hatua ya 5. Kuna nini kibaya na orodha ya ufikiaji

Ninaangalia orodha ya ufikiaji wa L3VPN ni nini:

Gate2#show access-list L3VPN
Extended IP access list L3VPN
    10 permit udp host 10.10.10.251 any eq isakmp
    20 permit udp host 10.10.10.251 any eq non500-isakmp
    30 permit icmp host 10.10.10.251 any

Ninaona kuwa pakiti za ISAKMP zinaruhusiwa, kwa hivyo handaki ya IPsec imeanzishwa. Lakini hakuna sheria ya kuwezesha kwa ESP. Inavyoonekana, mwanafunzi alichanganya icmp na esp.

Kuhariri orodha ya ufikiaji:

Gate2(config)#
ip access-list extended L3VPN
no 30
30 permit esp host 10.10.10.251 any

Hatua ya 6. Kuangalia utendaji

Kwanza kabisa, ninahakikisha kuwa orodha ya ufikiaji wa L3VPN ni sahihi:

Gate2#show access-list L3VPN
Extended IP access list L3VPN
    10 permit udp host 10.10.10.251 any eq isakmp
    20 permit udp host 10.10.10.251 any eq non500-isakmp
    30 permit esp host 10.10.10.251 any

Sasa ninazindua trafiki inayolengwa kutoka kwa kifaa R1:

root@R1:~# ping 1.1.1.2 -c 4
PING 1.1.1.2 (1.1.1.2) 56(84) bytes of data.
64 bytes from 1.1.1.2: icmp_seq=1 ttl=64 time=35.3 ms
64 bytes from 1.1.1.2: icmp_seq=2 ttl=64 time=3.01 ms
64 bytes from 1.1.1.2: icmp_seq=3 ttl=64 time=2.65 ms
64 bytes from 1.1.1.2: icmp_seq=4 ttl=64 time=2.87 ms

--- 1.1.1.2 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3006ms
rtt min/avg/max/mdev = 2.650/10.970/35.338/14.069 ms

Ushindi. Mtaro wa GRE umeanzishwa. Kaunta ya trafiki inayoingia katika takwimu za IPsec sio sifuri:

root@Gate1:~# sa_mgr show
ISAKMP sessions: 0 initiated, 0 responded

ISAKMP connections:
Num Conn-id (Local Addr,Port)-(Remote Addr,Port) State Sent Rcvd
1 3 (10.10.10.251,500)-(10.10.10.252,500) active 1474 1350

IPsec connections:
Num Conn-id (Local Addr,Port)-(Remote Addr,Port) Protocol Action Type Sent Rcvd
1 4 (172.16.0.1,*)-(172.17.0.1,*) 47 ESP tunn 1920 480

Kwenye lango la Gate2, katika matokeo ya klogview, jumbe zilionekana kuwa trafiki inayolengwa 172.16.0.1->172.17.0.1 ilisimbwa kwa ufanisi (PASS) na sheria ya LIST katika ramani ya crypto ya CMAP:

root@Gate2:~# klogview -f 0xffffffff
filtration result for in packet 172.16.0.1->172.17.0.1, proto 47, len 112, if eth0: chain 18 "IPsecPolicy:CMAP", filter 25, event id IPsec:Protect:CMAP:1:LIST, status PASS
passed in packet 172.16.0.1->172.17.0.1, proto 47, len 112, if eth0: decapsulated

Matokeo ya

Mwanafunzi aliharibu siku yake ya mapumziko.
Kuwa mwangalifu na sheria za ME.

Mhandisi asiyejulikana
t.me/mhandisi_asiyejulikana

Chanzo: mapenzi.com

Kuongeza maoni