BGP question about route propagation

[WallaceVanDunk1494]

I'm sure I'm tired and missing something stupid but at the moment, I can't figure out what it is so I'm back here again

I have 2 routers in GNS3, ISP1 and ISP2.  They're connected by a 4.2.2.0/30 link.  4.2.2.1 lives on ISP1, and 4.2.2.2 lives on ISP2.

ISP1 is also connected to another router, EDGE1.  ISP1 and ISP2 are in different AS's and are bgp peered across the 4.2.2.0/30 link.  ISP1 is also bgp peered with Edge1, also in a different AS.

If I go on Edge1, I can ping 4.2.2.1 just fine, but I cannot ping 4.2.2.2.  I tried issuing the "neighbor 4.2.2.2 next-hop-self" command on ISP1 thinking that would take care of it, but it didn't.  I assumed the packet would hit ISP1, and since 4.2.2.2 is directly connected via the /30, the packet would take care of itself, but this does not appear to be the case.

ISP1

ISP1(config-router-af)#do sh run | s bgp
router bgp 65111
 bgp log-neighbor-changes
 no bgp default ipv4-unicast
 neighbor 4.2.2.2 remote-as 65222
 neighbor 172.16.0.2 remote-as 65000
 !
 address-family ipv4
  network 4.2.2.0 mask 255.255.255.252
  network 172.16.1.0 mask 255.255.255.0
  network 172.16.2.0 mask 255.255.255.0
  network 172.16.3.0 mask 255.255.255.0
  network 172.16.4.0 mask 255.255.255.0
  neighbor 4.2.2.2 activate
  neighbor 4.2.2.2 next-hop-self
  neighbor 172.16.0.2 activate
 exit-address-family

ISP1(config-router-af)#do sh ip bgp
BGP table version is 11, local router ID is 172.16.4.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>  4.2.2.0/30       0.0.0.0                  0         32768 i
 *                    4.2.2.2                  0             0 65222 i
 *>  10.0.1.0/24      4.2.2.2                  0             0 65222 i
 *>  10.0.2.0/24      4.2.2.2                  0             0 65222 i
 *>  10.0.3.0/24      4.2.2.2                  0             0 65222 i
 *>  10.0.4.0/24      4.2.2.2                  0             0 65222 i
 *>  172.16.1.0/24    0.0.0.0                  0         32768 i
 *>  172.16.2.0/24    0.0.0.0                  0         32768 i
 *>  172.16.3.0/24    0.0.0.0                  0         32768 i
 *>  172.16.4.0/24    0.0.0.0                  0         32768 i

ISP2

ISP2#sh run | s bgp
router bgp 65222
 bgp log-neighbor-changes
 no bgp default ipv4-unicast
 neighbor 4.2.2.1 remote-as 65111
 neighbor 10.0.0.2 remote-as 65000
 neighbor 10.0.0.6 remote-as 65000
 !
 address-family ipv4
  network 4.2.2.0 mask 255.255.255.252
  network 10.0.1.0 mask 255.255.255.0
  network 10.0.2.0 mask 255.255.255.0
  network 10.0.3.0 mask 255.255.255.0
  network 10.0.4.0 mask 255.255.255.0
  neighbor 4.2.2.1 activate
  neighbor 10.0.0.2 activate
  neighbor 10.0.0.6 activate
 exit-address-family
ISP2#sh ip bgp 
BGP table version is 18, local router ID is 10.0.4.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *   4.2.2.0/30       4.2.2.1                  0             0 65111 i
 *>                   0.0.0.0                  0         32768 i
 *>  10.0.1.0/24      0.0.0.0                  0         32768 i
 *>  10.0.2.0/24      0.0.0.0                  0         32768 i
 *>  10.0.3.0/24      0.0.0.0                  0         32768 i
 *>  10.0.4.0/24      0.0.0.0                  0         32768 i
 *>  172.16.1.0/24    4.2.2.1                  0             0 65111 i
 *>  172.16.2.0/24    4.2.2.1                  0             0 65111 i
 *>  172.16.3.0/24    4.2.2.1                  0             0 65111 i
 *>  172.16.4.0/24    4.2.2.1                  0             0 65111 i

Edge1

EDGE1(config-router)#do sh run | s bgp
router bgp 65000
 bgp log-neighbor-changes
 no bgp default ipv4-unicast
 neighbor 10.0.0.1 remote-as 65222
 neighbor 172.16.0.1 remote-as 65111
 !
 address-family ipv4
  neighbor 10.0.0.1 activate
  neighbor 172.16.0.1 activate
 exit-address-family

EDGE1(config-router)#do sh ip bgp 
BGP table version is 29, local router ID is 192.168.0.18
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>  4.2.2.0/30       172.16.0.1               0             0 65111 i
 *>  10.0.1.0/24      172.16.0.1                             0 65111 65222 i
 *>  10.0.2.0/24      172.16.0.1                             0 65111 65222 i
 *>  10.0.3.0/24      172.16.0.1                             0 65111 65222 i
 *>  10.0.4.0/24      172.16.0.1                             0 65111 65222 i
 *>  172.16.1.0/24    172.16.0.1               0             0 65111 i
 *>  172.16.2.0/24    172.16.0.1               0             0 65111 i
 *>  172.16.3.0/24    172.16.0.1               0             0 65111 i
 *>  172.16.4.0/24    172.16.0.1               0             0 65111 i

You'll see some route advertisements that aren't currently relevant as I was starting to build a topology but stopped when I got to this point and forgot basic bgp >.<.  Thanks in advance for any help.

[TJ-20933766 · Accepted solution]

Edge1 is connected to ISP1 via 172.16.0.0/? subnet that is not being advertised with a "network" statement. As such ISP2 doesn't have that network in it's BGP table and doesn't know how to respond to traffic sourced from Edge1 (172.16.0.2). I believe adding the following command to ISP1 should fix the issue

router bgp 65222
 address-family ipv4
  network 172.16.0.0 mask 255.255.255.252

I'm guessing at what the subnet mask is for that connection but you get the idea. Let me know if that works and please consider rating my comment as helpful if it was!

[WallaceVanDunk1494]

Yup.  Return traffic issue.  I have issues thinking about return traffic when I'm tired >.<.  Thanks for the response.