Questions tagged [troubleshooting]

For questions requiring troubleshooting assistance with persistent/unresolved problems.

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2
votes
3answers
30k views

Output drops/errors on Cisco 3850

Sorry if this is a noob-ish question, but I am a bit lost. We are currently having some network issues, that seem to be manifesting in what appear to me to be odd ways. End result is I have some ...
0
votes
1answer
604 views

Three SG220-50P switches are rebooting randomly every few hours or days

We have three small business PoE switches, SG220-50P purchased from two places. They are each randomly rebooting at different times every few days, and sometimes only after a few hours. They have been ...
2
votes
3answers
2k views

Can't Ping INTERNET from clients but I CAN from Internal Routers

I have a gateway rv320 cisco(lets name it BR) and inter router Cisco 1921 (lets name it RTR) i was having trouble pinging the lan port on the BR from my hosts, but someone helped me fix that issue. ...
0
votes
1answer
43 views

Mixed Use Four-pair Cable

My school tried to save money, so they decide to use an installed cable for phone, CCTV, and ethernet. I used two pairs for ethernet, one for phone, and one for a CCTV camera. The phone and camera ...
1
vote
1answer
120 views

Trouble connecting a small network.. pinging

RTR configuration: service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname T-RTR ! boot-start-marker boot-end-marker ! ! enable secret 5 $...
2
votes
2answers
2k views

Multicast doesn't get forwarded correctly [closed]

I have a problem with UDP-Multicast with Kubernetes: I have to Kubernetes-Nodes each of them running a pod: Kubernetes-Node-1: - eth0: 192.168.0.2/24 - docker0: 10.1.1.1/24 Pod1 on Kubernetes-...
2
votes
2answers
2k views

I can't ping 8.8.8.8 from 2960 L2 switch?

I have new 2960 L2 switch, I can't ping 8.8.8.8 from switch but having internet on clients that connected to same switch
1
vote
2answers
316 views

Will wifi networks on same 2.4GHz channel conflict if only 1 is being used?

I think this is a simple yes/no question but I may be wrong. I work in a warehouse sized building where 4 networks are broadcasting but only 1 is being used, as in, no one logs in to the other ...
2
votes
1answer
60 views

Different responses IP and domain name [closed]

I have a domain name that is using a public IP, when I send two requests, one to the domain name and one to the IP I get different headers in each one, in one of them 4 cookies are set, in the other ...
1
vote
1answer
29 views

MLPPP_Bundle_load sharing [closed]

I have configured one MLPPP bundle with 6 E1`s. One of them getting utilize more than 80% while other one are just only 5 or 10 % utilize. How can i overcome from such issue.
16
votes
3answers
91k views

How to verify that a UDP port is open? [closed]

I have here a dilemma. I have a device that communicates to another remote device but there is a firewall between them. It's a UDP connection, so TCP utilities don't work to test if the specific port ...
1
vote
0answers
48 views

One of my MPLS link is not passing traffic [closed]

I have two MPLS link and one is not passing traffic the other is passing traffic. What can be the cause of it.
1
vote
1answer
73 views

How to assure where the problem is occurring? [closed]

I actually posted this question yesterday. I'm here to ask you guys again after testing. ↓↓↓First of all, please see my question↓↓↓ My customers told me that the access speed is really slow markedly!...
2
votes
1answer
75 views

Site-to-Site VPNs

I'm having some problems with our networks and I'm wondering if anyone has some ideas. We have recently moved to a cloud server (we went with UKFast) to host our network - it's main use is for the ...
1
vote
0answers
292 views

Effects of ip options drop command on Cisco 4507 Device

Are there any services or applications traversing a router that will be impacted by the command, "ip options drop"? I know the router warns about RSVP when you input this command, but this 4510 is not ...
2
votes
1answer
420 views

Static NAT using IP address from different address space

How to do NAT if I need translate PC IP to IP address f.e. 130.130.130.130? I set ip nat inside and ip nat Outside interface and there is also OSPF between routers and server. I use ip nat inside ...
1
vote
1answer
883 views

How to find the end-device causing high cpu usage in a Cisco switch? [closed]

While checking: sh proc cpu history there is high CPU utilization which occurs at a particular time.
3
votes
2answers
789 views

NetFlow-working one direction only

Cisco 3850/IP Base/IOS XE 3.7.2 I was going over my NetFlow data, and it seemed I was only catching flow in, and not out. I already had the in/out records and monitors, using the same exporter to one ...
1
vote
2answers
900 views

can switch make lan slow [closed]

i have network in my office which i roughly described in images. pc1(Ethernet) and laptop(via wifi) is connected directly to router, and pc2 and pc3 is connected via switch in both in Ethernet. when ...
4
votes
1answer
384 views

Latency in P2P Circuit

I have one P2P Circuit from our HQ to a secondary office. the distance between them is approx 2kms. Earlier when the Circuit was delivered at that time we were having an RTT of 3-4ms. It is a 10Mbps ...
1
vote
1answer
4k views

Input packet drops on port channel

I have a certain number of packets dropped on my port channel interface with 3gbps bundled speed, on Cisco 6500 with Sup 720. You can see underneath the number of dropped packet within a minute, after ...
1
vote
0answers
100 views

「Netscreen」 VPN UP/DOWN due to loopback address source monitoring

I am dealing with a problem with Netscreen VPN. Topology is basically Server Side ーー> (Agg2)Trust/Untrust(Agg1)ーー> ーー> Remote Office (Yamaha) 100.66.xx.0/24 ーー> Netscreen VPN ーー> Internet ーー> 100....
4
votes
4answers
410 views

How do I fix my vlans connection to the Internet?

I have the following abridged configuration for a Ubiquiti switch: interfaces { ethernet eth1 { address 192.168.4.1/24 vif 101 { address 10.10.254.1/24 } ...
1
vote
1answer
845 views

Is NAT loopback the only reason I can't view my own website from within my LAN? [closed]

I am new to this so apologies if this is the wrong place for such a question. I'm testing out a simple "hello world" website hosted at home. As we have not been assigned a static IP address by our ...
2
votes
2answers
101 views

Effects of local switch time on network performance

Given a collection of switches all communicating together, will the local time on the switching equipment configuration have any bearing on performance, or just a common reference point when ...
0
votes
1answer
50 views

Troubleshooting server connectivity [closed]

I went for an interview recently and I was asked if a server was experiencing slow file transfer what would you do troubleshoot the issue? The could only think of checking speed/duplex. What else can ...
0
votes
1answer
74 views

Simple way to monitor network performance w/o access to network infrastructure?

I work for a large organization where the network team is in some disarray (key people left/fired, etc.). My team is responsible for the performance of various client/server applications which of ...
5
votes
4answers
8k views

DLink switch loses configuration on power off!

We just bought a DGS-1210-28P smart switch, it is my first experience with a business class switch, however I found a pretty weird behavior. The switch loses all of its configurations, even management ...
4
votes
3answers
811 views

How can I know about if there is a smurf attack on my network?

I have been having network issues. The users report to me problems with the internet, but actually the problem is on my network. I have a sonicwall firewall and the device logs indicate posible tcp ...
4
votes
1answer
1k views

How to troubleshoot reason why ARP replies from ISP are not forwarded through our switch?

At one of our offices, a new ISP recently installed an Internet connection via Radwin microwave radios, going to an E1 line back to the capital where their routing equipment is. There is a very ...
2
votes
1answer
308 views

Allow outgoing connections

I have an Arista switch (EOS) and I'm having trouble allowing outgoing connection from the switch to the outside. Using tcpdump I can see that no packets are being allowed. This has an impact on DNS ...
6
votes
4answers
17k views

How do I pinpoint bandwidth consumers on my Fortigate?

For a long time now we've been having huge connection problems at work. The Internet connection is bad, for sure, but I don't think they are the main problem, they don't see any packet loss on their ...
-1
votes
2answers
212 views

network problems

I am having a problem with my network. I have a router (R1) connected to another router (R2) R1 is connected to a switch. R1 switch has two PC's connected to it. the PC IP's are 128.107.35.10 and 192....
-2
votes
1answer
89 views

Does the bandwidth of a Comcast modem divide if it is connected to two routers on two subnets? [closed]

I have a 150 megabits/sec Comcast pipe that connects to two subnets through two Cisco routers. The bandwidth at the modem is 150 Mb/s. The bandwidth at one router is 96 Mb/s and the other is 96 Mb/s ...
1
vote
1answer
88 views

Question about graceful restart

i do some research on graceful restart for OSPF, BGP, LDP. After i read those RFCs for these protocols, i have a question want to ask that if a router really goes down not restart (i.e. power off...), ...
1
vote
2answers
883 views

ISP router unreachable by PAT

I just configured PAT in a router but it doesn't work ,, I write this commands in R1 access-list 4 permit 172.16.0.0 0.0.255.255 ip nat pool AdeNet 80.80.10.20 80.80.10.20 netmask 255.255....
6
votes
2answers
7k views

Juniper EX2200 can't boot

I recently acquired a Juniper EX2200-24T-4G switch, but I have some issues getting it up and running. When I power on the switch the boot process looks normal, but after some time it suddenly turns ...
3
votes
2answers
8k views

Cisco router telnet troubleshooting - connection timeout; unresponsive host

I cannot figure out how to establish a telnet connection between two routers in Cisco Packet Tracer. This is a relatively simple process, I know, but I have been back and forth looking for how to fix ...
2
votes
1answer
544 views

HW State: DEAD - Cisco 3925

I received an alert stating that a crypto engine was 'dead'. I did a bit of digging and was able to find some output to validate this: #sh crypto eng config crypto engine name: Virtual Private ...
0
votes
1answer
640 views

Finding bad node in a network [closed]

If I have two sites from where I connect to a separate server in a remote location. From 1 site I can connect fine, i.e. good response times etc. However from the other site I cannot connect and the ...
2
votes
0answers
659 views

Palo Alto Layer 7 [closed]

I've got the following error for a security policy in PA 3020: L7 processing ; ctd error bypass I tried Googling, but I couldn't find a solution. Does anyone knows the meaning of this? The ...
2
votes
3answers
6k views

TAC Response on the error( %SYS-2-MALLOCFAIL: Memory allocation)

I hope you can offer me some assistance with my case, we have a Cisco router 2800 series ,having the error ( %SYS-2-MALLOCFAIL: Memory allocation), (and if restarted the router it works OK for while. ...
8
votes
4answers
2k views

Internal BGP route exchange issue

I have BGP multihoming with two cisco routers. Each router has its own ISP and announce our AS with our /24 network to the internet. My issue is between those two routers : Router A, routing table ...
0
votes
3answers
121 views

Is a high TCP retransmittal % a conclusive indication of congestion?

I have a web server who's perfmon stats report a TCP retransmittal rate of about 10%. I also have a client who makes heavy use of this server reporting poor performance. The performance problems ...
3
votes
1answer
501 views

Problem with IP phones after ISP failover change

I've ran into a strange problem at one of my clients. They use ShoreTel Sky cloud IP telephony service and use Cisco 7960 IP phones hooked up to an ASA 5520. The configuration is done through IP SLA ...
8
votes
1answer
5k views

Unpredictable Juniper SNMPv3 Access Error

We're having issues where SNMPv3 ceases to accept SNMP requests on our Juniper EX series switches. In what seems like random occurrences, Juniper nodes refuse SNMP authentication credentials. This ...
11
votes
4answers
46k views

Interpreting TTL in ping results

I work for a VoIP service provider and I am working an issue with a customer who has a cable internet connection that's throwing me for a loop. He has a single block, which we'll pretend is 70.141.15....
4
votes
2answers
8k views

How to configure Internet Port and Public IP settings on the CISCO Meraki Z1?

What exactly do the Internet Port and Public IP settings mean on the CISCO Meraki Z1 gateway? Context Note: this is a detailed explanation with images - I apologize for its length but I'm striving ...
6
votes
1answer
1k views

Split Horizon will not disable on interface

I'm trying to set up a DMVPN Phase 2 configuration, but I cannot manage to get past Phase 1 because the hub router's tunnel interface refuses to disable split-horizon. The spokes never form an EIGRP ...
4
votes
2answers
718 views

Multiple error types Cisco 861 router

I have a connection that users complain is really slow at times. My SNMP graphs from Observium don't show the bandwidth being fully used or high latency. They show a lot of errors on the WAN port of ...