wondering about default route and no routes

Answered Question
Dec 14th, 2009

initially i had a mgt router with an ip address of 192.168.119.250. I was unable to telnet to it from my desktop which sits on another subnet

I was however able to telnet to it from the gw. When i logged into the router i noticed the default gateway was missing.

So I added that and was able to telnet  to it remotely

My question is however,

This..

I have a snmp server in a subnet.......I also have a Border router that connets directly to our ISP.

I was able to pull snmp information from it using an ip address on it that is connected to our fw.

My question is...

Since there is no routing information on the border router itself to my internal network...how was the traffic able to return?

here is the routing informaion

the snmp host is 10.11.13.234

R1.T1#sh ip route 10.11.13.234
% Network not in table
R1.T1#

BR1.CLT1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

router bgp 1xxxx7
no synchronization
bgp log-neighbor-changes
network 6x.2xx.xx6.0 mask 255.255.252.0
redistribute connected
redistribute static
neighbor 65.xx3.xx6.2 remote-as 1xxxx7
neighbor 1x7.xxx.xx.173 remote-as 7xxx
neighbor 2x9.xxx.xxx.253 remote-as xxxx9
neighbor 2x9.xx9.xx.xx3 password xxxxq
neighbor 2x9.xx.xx.53 ebgp-multihop 6
neighbor 2x9.xx.16.x53 prefix-list to-7xx9 out
no auto-summary


Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
65.xxx.xxx.2    4 19657 1609169 2533617 151819621    0    0 7w3d       124042-----connected to our fw
1x7.xxx.xx.173  4   701 2898768 1016682 151819611   12    0 7w1d       299994------internet link
2xx.xx.xx.xx53   4  7349 12506458  345419 151819611    9    0 31w2d      302063--secondary internet link

I have this problem too.
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Correct Answer by Jon Marshall about 6 years 11 months ago

nygenxny123 wrote:

initially i had a mgt router with an ip address of 192.168.119.250. I was unable to telnet to it from my desktop which sits on another subnet

I was however able to telnet to it from the gw. When i logged into the router i noticed the default gateway was missing.

So I added that and was able to telnet  to it remotely

My question is however,

This..

I have a snmp server in a subnet.......I also have a Border router that connets directly to our ISP.

I was able to pull snmp information from it using an ip address on it that is connected to our fw.

My question is...

Since there is no routing information on the border router itself to my internal network...how was the traffic able to return?

here is the routing informaion

the snmp host is 10.11.13.234

R1.T1#sh ip route 10.11.13.234
% Network not in table
R1.T1#

BR1.CLT1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

router bgp 1xxxx7
no synchronization
bgp log-neighbor-changes
network 6x.2xx.xx6.0 mask 255.255.252.0
redistribute connected
redistribute static
neighbor 65.xx3.xx6.2 remote-as 1xxxx7
neighbor 1x7.xxx.xx.173 remote-as 7xxx
neighbor 2x9.xxx.xxx.253 remote-as xxxx9
neighbor 2x9.xx9.xx.xx3 password xxxxq
neighbor 2x9.xx.xx.53 ebgp-multihop 6
neighbor 2x9.xx.16.x53 prefix-list to-7xx9 out
no auto-summary


Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
65.xxx.xxx.2    4 19657 1609169 2533617 151819621    0    0 7w3d       124042-----connected to our fw
1x7.xxx.xx.173  4   701 2898768 1016682 151819611   12    0 7w1d       299994------internet link
2xx.xx.xx.xx53   4  7349 12506458  345419 151819611    9    0 31w2d      302063--secondary internet link

Do you have to go through the firewall to get to the router ?

If so are you Natting/Patting source addresses as they go through the firewall. If you are that may well be the answer because the firewall changes the source address to it's outside interface which your border router knows how to get to.

Jon

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Correct Answer
Jon Marshall Mon, 12/14/2009 - 11:44

nygenxny123 wrote:

initially i had a mgt router with an ip address of 192.168.119.250. I was unable to telnet to it from my desktop which sits on another subnet

I was however able to telnet to it from the gw. When i logged into the router i noticed the default gateway was missing.

So I added that and was able to telnet  to it remotely

My question is however,

This..

I have a snmp server in a subnet.......I also have a Border router that connets directly to our ISP.

I was able to pull snmp information from it using an ip address on it that is connected to our fw.

My question is...

Since there is no routing information on the border router itself to my internal network...how was the traffic able to return?

here is the routing informaion

the snmp host is 10.11.13.234

R1.T1#sh ip route 10.11.13.234
% Network not in table
R1.T1#

BR1.CLT1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

router bgp 1xxxx7
no synchronization
bgp log-neighbor-changes
network 6x.2xx.xx6.0 mask 255.255.252.0
redistribute connected
redistribute static
neighbor 65.xx3.xx6.2 remote-as 1xxxx7
neighbor 1x7.xxx.xx.173 remote-as 7xxx
neighbor 2x9.xxx.xxx.253 remote-as xxxx9
neighbor 2x9.xx9.xx.xx3 password xxxxq
neighbor 2x9.xx.xx.53 ebgp-multihop 6
neighbor 2x9.xx.16.x53 prefix-list to-7xx9 out
no auto-summary


Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
65.xxx.xxx.2    4 19657 1609169 2533617 151819621    0    0 7w3d       124042-----connected to our fw
1x7.xxx.xx.173  4   701 2898768 1016682 151819611   12    0 7w1d       299994------internet link
2xx.xx.xx.xx53   4  7349 12506458  345419 151819611    9    0 31w2d      302063--secondary internet link

Do you have to go through the firewall to get to the router ?

If so are you Natting/Patting source addresses as they go through the firewall. If you are that may well be the answer because the firewall changes the source address to it's outside interface which your border router knows how to get to.

Jon

nygenxny123 Wed, 12/16/2009 - 20:05

Hi John,

I just did a traceroute from the snmp server..since i am using a public address to pull snmp from-( the router only has 2 ips configured on it..both public ip's).....I get routed to the internet and back to the router in question,,,

However...whats odd is can pull just the basic snmp information -router hostname, IOS version..but not things such and bandwidth utilization

isnt this using the same port?..161?

i believe all outband traffic is free from the internet..and this router is directly connected to the internet.

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