spring RestTemplate not resolving eureka names - spring

Question

I have 1 eureka server and 2 microservices. They are called oauth and authentication. I start up everything and the 2 microservices register to eureka. I can verify that by typing the url of the eureka server in my browser.
I now want to use a resttemplate so that oauth microservice can communicate with authentication microservice.
In my class I have added this autowired
#Autowired
private RestTemplate restTemplate;
I then use this following code to communicate from oauth microservice to the authentication microservice.
ResponseEntity<ResponseDto<?>> responseEntity = restTemplate.exchange("http://authentication/api/authentication/verify",
HttpMethod.POST, request, typeRef);`
When this code is executed I see this in my logs:
oauth | 2018-11-30 13:41:58.535 INFO 1 --- [nio-9001-exec-1] s.c.a.AnnotationConfigApplicationContext : Refreshing SpringClientFactory-authentication: startup date [Fri Nov 30 13:41:58 GMT 2018]; parent: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext#6743e411
oauth | 2018-11-30 13:41:58.641 INFO 1 --- [nio-9001-exec-1] f.a.AutowiredAnnotationBeanPostProcessor : JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
oauth | 2018-11-30 13:41:59.115 INFO 1 --- [nio-9001-exec-1] c.netflix.config.ChainedDynamicProperty : Flipping property: authentication.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
oauth | 2018-11-30 13:41:59.150 INFO 1 --- [nio-9001-exec-1] c.n.u.concurrent.ShutdownEnabledTimer : Shutdown hook installed for: NFLoadBalancer-PingTimer-authentication
oauth | 2018-11-30 13:41:59.221 INFO 1 --- [nio-9001-exec-1] c.netflix.loadbalancer.BaseLoadBalancer : Client: authentication instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=authentication,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
oauth | 2018-11-30 13:41:59.237 INFO 1 --- [nio-9001-exec-1] c.n.l.DynamicServerListLoadBalancer : Using serverListUpdater PollingServerListUpdater
oauth | 2018-11-30 13:41:59.303 INFO 1 --- [nio-9001-exec-1] c.netflix.config.ChainedDynamicProperty : Flipping property: authentication.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
oauth | 2018-11-30 13:41:59.310 INFO 1 --- [nio-9001-exec-1] c.n.l.DynamicServerListLoadBalancer : DynamicServerListLoadBalancer for client authentication initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=authentication,current list of Servers=[{MYSERVERSIP}:9003],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone; Instance count:1; Active connections count: 0; Circuit breaker tripped count: 0; Active connections per server: 0.0;]
oauth | },Server stats: [[Server:{MYSERVERSIP}:9003; Zone:defaultZone; Total Requests:0; Successive connection failure:0; Total blackout seconds:0; Last connection made:Thu Jan 01 00:00:00 GMT 1970; First connection made: Thu Jan 01 00:00:00 GMT 1970; Active Connections:0; total failure count in last (1000) msecs:0; average resp time:0.0; 90 percentile resp time:0.0; 95 percentile resp time:0.0; min resp time:0.0; max resp time:0.0; stddev resp time:0.0]
oauth | ]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList#1c33a40d
oauth | 2018-11-30 13:42:00.250 INFO 1 --- [erListUpdater-0] c.netflix.config.ChainedDynamicProperty : Flipping property: authentication.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
oauth | 2018-11-30 13:44:06.826 INFO 1 --- [nio-9001-exec-1] o.s.s.o.provider.endpoint.TokenEndpoint : Handling error: InternalAuthenticationServiceException, I/O error on POST request for "http://authentication/api/authentication/verify": Operation timed out (Connection timed out); nested exception is java.net.ConnectException: Operation timed out (Connection timed out)
I can access the authentication microservice from my home computer so that means the port is open. I have tried the #LoadBalanced annotation however that doesn't work.
What is going on?????

Answer 1

I found the solution. It turns out I had an iptables rule that was blocking the request. So if this happens to you then check your iptables rules.